Re: [time-nuts] Beaglebone NTP server
On my rpi the jitter is between 2 and 10us iirc but it is a while since I tested it. A quick peak shows me currently 3us jitter. Not bad for a userspace solution imho. Really? The PPS to GPIO interface is handles in user space? It is not interrupt driven? Yes it is. But, until today, I used a software solution which interfaces the interrupt to ntp. I did that because I hate recompiling kernels and the pps code for rpi+gpio was not in the main distrio. Folkert van Heusden -- Ever wonder what is out there? Any alien races? Then please support the seti@home project: setiathome.ssl.berkeley.edu -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Am 11.12.2014 um 22:23 schrieb Hal Murray: It's not uncommon to archive the PC that has all the tools when a significant hardware project is released. Just put a big note on it and push it into a closet in case you ever need it again. (Setting up CAD tools is often quirky and hard to debug.) Again, this needs documentation. Suppose you want to make a simple one line change to fix a typo. What do you do to turn the crank and make the files you hand off to the next step? I must have been quite a bugger in an earlier incarnation, so in this life I'm condemned to finalize some space bound original Xilinx Virtex FPGAs that have been conceived a looong time ago. That ISE10.1 software seems to store state deep in its dungeons like paths to libraries on servers or signal names that pop up after being removed a long time. ISE should be forbidden. I now keep everything I need for a chip in a virtual XP machine, and nothing else, and save the entire machine in regular intervalls. There fit a lot of 50G machines on a 3 TByte external disk. VMware is my friend. regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Let's say you had followed this advice in 2004 or 1999. You build a single purpose NTP server out of whatever was the best smaller server platform back in 1999 and today it broke. Even if you could, would you want to replace it with a 1999 vintage small server computer? No way. You'd notice the BBB as being better, lower priced and using less power. So I assume that in 2029 when the BBB fails after 15 years there is no way you even want anther BBB. For one thing the BBB would not run any OS that you were foamier with. It would not run the current best version of the software and. Actually my 1999 vintage small server was replaced BEFORE it failed because it was burning about $8 in electric power per month. That adds up over a 10 year period. It got replaced with something that uses a tiny fraction of that power and paid for itself. On Thu, Dec 11, 2014 at 1:23 PM, Hal Murray hmur...@megapathdsl.net wrote: jim...@earthlink.net said: Ah, but will the exact same single board computer be available for replacement in 5 years? Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? My straw man is to buy a bunch now and put them on the shelf until you need them? It would be interesting to read a good B-school type report on that topic. Is it realistic to expect any electronics related stuff to be available for 10 years? I think I've seen a few boards marked long-lifetime. I don't remember the details. At least one OS distro has a version marked long-lifetime, but I don't know how long that covers. What does the military do for this problem? What's the average lifetime of something like a radio in a military plane? How often do they get upgraded because the old ones are no longer maintainable due to unavailability of parts? What's the average lifetime of a fab line? Or even the max lifetime? (in case you are a big vendor with multiple fab lines for a particular technology) What's the typical lifetime of parts used in timing related gear? Maybe that's the key.. think of it as an appliance. If it stops working, and it's not because of something simple (power cord), then you're probably better off building a new one from scratch than trying to fix the old one. That is, the labor involved in port to a new platform might be substantially less than find old platform and install it in old box, if only because things like tool chains tend to follow the latest hardware. A lot of that depends on the quality of the documentation you kept when you set things up. I've worked with guys who were good at making a big pile of kludgy gear jump through hoops. One of them was very good at writing down what he did. It doesn't have to be a fancy document blessed by 43 proofreaders, but it really helps to mention all the critical steps and/or explain the non-obvious reasons for doing things. I've gotten into the habit of making a checklist of what I have to do to install distro-X from CD and fix it up to do what I want. Every now and then, I want another box just like that one except... It isn't fancy, but it does have a line to remind me about each file that needs editing and what tools are used to set things up. Often there are chunks of code I can cut-paste. Even if you kept the tool chain for your old platform, running it on a new computer might be problematic. (recognizing that there are people out there running IBM 1401 emulators on System/360 emulators on... but that takes time too) It's not uncommon to archive the PC that has all the tools when a significant hardware project is released. Just put a big note on it and push it into a closet in case you ever need it again. (Setting up CAD tools is often quirky and hard to debug.) Again, this needs documentation. Suppose you want to make a simple one line change to fix a typo. What do you do to turn the crank and make the files you hand off to the next step? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi The most likely case is that the power supply goes out long before the rest of the server. At least that’s what happens around here. Same net result, if the supply took the board with it (replace with same or newer). Likely same result even if it’s just the supply (replace everything). Bob On Dec 12, 2014, at 9:42 AM, Chris Albertson albertson.ch...@gmail.com wrote: Let's say you had followed this advice in 2004 or 1999. You build a single purpose NTP server out of whatever was the best smaller server platform back in 1999 and today it broke. Even if you could, would you want to replace it with a 1999 vintage small server computer? No way. You'd notice the BBB as being better, lower priced and using less power. So I assume that in 2029 when the BBB fails after 15 years there is no way you even want anther BBB. For one thing the BBB would not run any OS that you were foamier with. It would not run the current best version of the software and. Actually my 1999 vintage small server was replaced BEFORE it failed because it was burning about $8 in electric power per month. That adds up over a 10 year period. It got replaced with something that uses a tiny fraction of that power and paid for itself. On Thu, Dec 11, 2014 at 1:23 PM, Hal Murray hmur...@megapathdsl.net wrote: jim...@earthlink.net said: Ah, but will the exact same single board computer be available for replacement in 5 years? Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? My straw man is to buy a bunch now and put them on the shelf until you need them? It would be interesting to read a good B-school type report on that topic. Is it realistic to expect any electronics related stuff to be available for 10 years? I think I've seen a few boards marked long-lifetime. I don't remember the details. At least one OS distro has a version marked long-lifetime, but I don't know how long that covers. What does the military do for this problem? What's the average lifetime of something like a radio in a military plane? How often do they get upgraded because the old ones are no longer maintainable due to unavailability of parts? What's the average lifetime of a fab line? Or even the max lifetime? (in case you are a big vendor with multiple fab lines for a particular technology) What's the typical lifetime of parts used in timing related gear? Maybe that's the key.. think of it as an appliance. If it stops working, and it's not because of something simple (power cord), then you're probably better off building a new one from scratch than trying to fix the old one. That is, the labor involved in port to a new platform might be substantially less than find old platform and install it in old box, if only because things like tool chains tend to follow the latest hardware. A lot of that depends on the quality of the documentation you kept when you set things up. I've worked with guys who were good at making a big pile of kludgy gear jump through hoops. One of them was very good at writing down what he did. It doesn't have to be a fancy document blessed by 43 proofreaders, but it really helps to mention all the critical steps and/or explain the non-obvious reasons for doing things. I've gotten into the habit of making a checklist of what I have to do to install distro-X from CD and fix it up to do what I want. Every now and then, I want another box just like that one except... It isn't fancy, but it does have a line to remind me about each file that needs editing and what tools are used to set things up. Often there are chunks of code I can cut-paste. Even if you kept the tool chain for your old platform, running it on a new computer might be problematic. (recognizing that there are people out there running IBM 1401 emulators on System/360 emulators on... but that takes time too) It's not uncommon to archive the PC that has all the tools when a significant hardware project is released. Just put a big note on it and push it into a closet in case you ever need it again. (Setting up CAD tools is often quirky and hard to debug.) Again, this needs documentation. Suppose you want to make a simple one line change to fix a typo. What do you do to turn the crank and make the files you hand off to the next step? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Beaglebone NTP server
Getting a BBB to take 10MHz refclk input (in the fashion of http://www.febo.com/pages/soekris/) and being able to timestamp _multiple_ PPS signals via the PRUs would make for a pretty awesome time-nuts toy. This is quite do-able and I posted a few weeks ago with the details of where to poke the soldering iron. https://www.febo.com/pipermail/time-nuts/2014-November/088385.html Once you attach a bit of coax the only limit is how deep your pockets are, you can use whatever reference you want to clock the BBB. An OXCO will likely provide the best performance for most of us (for the same reasons as using one in a GPSDO). For kicks, I ran my BBB locked directly to a GPS module for a short while. That is, using a x12 PLL to create 24mhz from a ublox module configured to output 2mhz. (I don't recommend anyone actually uses this configuration btw, but it was fun to actually see it work) Cheers Simon ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Just to echo that using the PRU cores is the wrong way to go, the BBB has a multitude of hardware timers that will give better performance for less hassle. Having said that, by far the Number One thing to consider is controlling the impact of temperature changes. If you sort that, the rest is icing on the cake. In order of complexity: Out the box, using gpio-pps, the BBB is a good NTP server that will hold its own against other SoC solutions. Stick it in a box to control the temperature a bit and run Dan Drown's gmtimer-pps, you'll get a great NTP server. https://www.febo.com/pipermail/time-nuts/2014-December/089217.html This is an easy, quick win that will give excellent results. Add PTP and you should be able to sync time to other boxes at sub microsecond levels. But because we don't stop with 'just' great solutions ... Dan has been looking at software compensation to control the temperature impact. https://www.febo.com/pipermail/time-nuts/2014-November/087745.html I took a more brute force approach and clocked the BBB from a more stable reference. https://www.febo.com/pipermail/time-nuts/2014-November/088385.html Cheers Simon On 10/12/2014 23:56, Paul wrote: On Wed, Dec 10, 2014 at 4:58 PM, Brian Lloyd br...@lloyd.aero wrote: Well, I am hoping to get to the point where the path to using the BBB as an NTP server using the PRU for more precise timing Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. Naturally if you're doing significant computing (heh) on the BBB you might want to use a real time unit. The current portion of this thread is part of the June-2013 hread started by Gabs Ricalde about using TIMER4 for capture with 10MHz/1PPS input. https://www.febo.com/pipermail/time-nuts/2013-June/077430.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 11/12/2014 04:15, Chris Albertson wrote: Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? The BBB scores over the Pi here in having real hardware ethernet instead of USB ethernet. Better, the BBB has hardware support for IEEE1588 timestamping so you can ditch NTP and distribute time using the BBB as a PTP grandmaster. The software is mature, but unfortunately a kernel rebuild is required to enable the appropriate drivers. The attached graph shows an overnight test using two BBBs connected via a normal (i.e. non-IEEE1588) gigabit switch. The offset graphed is as reported by PTP on the slave, the black line is a moving 100 point average and the scale is in ns. The stddev offset over the period is about 260ns. Cheers Simon ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/10/14, 9:45 PM, Mike Cook wrote: Le 11 déc. 2014 à 05:47, Brian Lloyd br...@lloyd.aero a écrit : On Wed, Dec 10, 2014 at 10:15 PM, Chris Albertson albertson.ch...@gmail.com wrote: Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? When I think of what we have been using to run NTP down through the years, this is almost funny. The BBB is little in physical package size only. Its processing power is not inconsequential. The question for anyone using them for other than personal use may be long term reliability. My three Soekris 4501s all died from power supply failiurs after 5 years contnuous use, while the 4801s have 6 years under the belt and still going strong. Will the RPIs and BBBs systematic issues or still be running after the same time? Of course 5 years is not that bad when S1 NTP servers are dedicated to that. Also the cost is so low that replacement isn’t a problem. A no brainer really. Ah, but will the exact same single board computer be available for replacement in 5 years? Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? Philosophically it might be a straightforward thing, but it might not be as easy as one might hope. Legacy support with processor boards is a real challenge. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thursday, December 11, 2014, Jim Lux jim...@earthlink.net wrote: Ah, but will the exact same single board computer be available for replacement in 5 years? Most likely not. These days I can't imagine a manufacturer making the same SBC or mobo board for more than a year. If you consider BBB to be the logical continuance of the original beagle board then it is going on two years but is at rev C. Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? If that is an issue, buy a spare and keep it in the same box with each running one. Heck, buy two spares. Philosophically it might be a straightforward thing, but it might not be as easy as one might hope. Legacy support with processor boards is a real challenge. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Your logic would disqualify EVERY computer made today. What will still be in production in 10 years? If you care a lot about reliantly you install three NTP servers on your network. Further you make sure each server is DIFFERENT and uses a different brand of GPS. You configure them all as peers. You'd still have a redundant system after a failure. I don't see why you'd want to replace the failed it with one that is identical because in several years there will likely be something even better at lower cost. The above comment about BBB having a good hardware Ethernetreally does make the BBB seem suited to this task. ButNTP is such a small load that you can run other services too. A file server (NAS) seems reasonable. On Thu, Dec 11, 2014 at 5:13 AM, Jim Lux jim...@earthlink.net wrote: Ah, but will the exact same single board computer be available for replacement in 5 years? Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? Philosophically it might be a straightforward thing, but it might not be as easy as one might hope. Legacy support with processor boards is a real challenge. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
The CPU temperature as measured by the on-CPU sensor went from about 55C to about 60C. 300MHz to 1GHz, ondemand, CPU in red http://dan.drown.org/bbb/run9/temp.png 1GHz fixed, CPU in red http://dan.drown.org/bbb/run8/temp.png For current drain, I only have numbers at the wall wart measured by a kill-a-watt. The entire system goes from 0.02A/1W to 0.04A/2W. Power Factor is in the 0.5~0.4 region. For the pins, that is correct. I chose P8.7 because it was TIMER4's input, and I can switch between pps-gpio and pps-gmtimer by changing which dts overlay I'm using. Quoting Graham / KE9H ke9h.gra...@gmail.com: When you forced/locked the CPU frequency at 1 GHz, did you by any chance measure what it did to the CPU case/package temperature? Or current drain? I note that you used BBB pin P8.7 for PPS input. That allowed you to use it for either pps-gpio or TIMER4 pps-gmtimer, by just changing the pin-mux? --- Graham == On Wed, Dec 10, 2014 at 7:58 PM, Dan Drown dan-timen...@drown.org wrote: Quoting Paul tic-...@bodosom.net: Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. As a note to people wanting to use the timer hardware on the BBB - I have a driver for it at https://github.com/ddrown/pps-gmtimer I wrote up the results in using it at http://blog.dan.drown.org/ beaglebone-black-timer-capture-driver/ The summary of it is: pps-gpio - 50% of the time local clock offset within +/- 0.07us, 98% within +/- 0.61us pps-gmtimer - 50% of the time local clock offset within +/- 0.04us, 98% within +/- 0.43us Also, if you're using pps-gpio, you might want to disable cpufreq and force your processor to 1GHz. It'll help with interrupt latency and jitter. cpufreq ondemand, 300MHz-1GHz - http://dan.drown.org/bbb/run9/ interrupt-latency.png 98% of interrupts handled 12.92us-23.21us after the event happened. cpufreq forced 1GHz - http://dan.drown.org/bbb/run8/interrupt-latency.png 98% of interrupts handled 6.04us-8.58us after the event happened. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 8:13 AM, Jim Lux jim...@earthlink.net wrote: Philosophically it might be a straightforward thing, but it might not be as easy as one might hope. Legacy support with processor boards is a real challenge. Which is why you don't do it this (ot that) way. The little SoC boxes are great but for most people doing NTP S1 they're either overkill (almost everyone not a national lab) or inadequate. Michael Tharp's products have shown the way forward for anyone that doesn't want to go with Meinberg et.al . ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/11/14, 6:14 AM, Brian Lloyd wrote: On Thursday, December 11, 2014, Jim Lux jim...@earthlink.net wrote: Ah, but will the exact same single board computer be available for replacement in 5 years? Most likely not. These days I can't imagine a manufacturer making the same SBC or mobo board for more than a year. If you consider BBB to be the logical continuance of the original beagle board then it is going on two years but is at rev C. Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? If that is an issue, buy a spare and keep it in the same box with each running one. Heck, buy two spares. I'm not sure that's a valid approach.. because eventually, the spares fail, or there's some crippling problem (year 2000 problems hardcoded in something, etc) At JPL, we are somewhat cursed by the fact that we don't depreciate our test equipment and computers. It's expensed in the year you buy it, and then it is essentially free forever (subject to calibration and maintenance costs). Therefore we have a lot of really old equipment around, and new systems are designed and built incorporating the old equipment. But when the last unit of that old model fails, now you have to update everything and jump multiple generations at one time, which is difficult. You've got a lot of learned history and designs that rely on idiosyncracies of a particular model (e.g. the 8663A, which happens to do phase continuous sweeping and can be phase modulated directly). And now, your venerable 8663 fails. The new replacement model (e.g. the E8663B) is functionally quite similar, has all the same specs (maybe even better in some cases), but, oops, it doesn't do phase continuous sweeping (because the synthesis chain is different). Rather than figure out how to solve the need with the newer gear, this leads to a scrounge fest. You get the institutional inventory and surplus list out and start calling up people who have seem to have another 8663A that hopefully they're not using and/or that it actually works. We've got stacks of dead 8663s sitting around, in, I think, the forlorn hope that someone will be able to cannibalize them for repair parts. The problem is even worse with PCs, because the support cycle time is shorter. The wailing, gnashing of teeth, and pulling of hair when NT 4.0 and later WinXP was declared OS non grata was amazing. Data acquisition systems, lab controllers, etc. all running WinXP and connected to the network as part of their function. Upgrading your software from NT to WinXP to Vista then to 7 then to 8 isn't as painful as jumping from NT to 8. Linux isn't a whole lot better. If you have a system you cobbled together in 2004 that was tied, say, to the typical audio system of the time, odds are that you're in for a real challenge to drop it into a modern distro with modern motherboard hardware. Which version of glibc? OSS audio? parallel port drivers? Oh, your new mobo doesn't HAVE a parallel printer port? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 9:45 AM, Chris Albertson albertson.ch...@gmail.com wrote: Your logic would disqualify EVERY computer made today. What will still be in production in 10 years? The ones you make yourself. Or if you're a nation-state the ones you have made to your specifications which include N years of support, or the ones you make yourself. Most time-nuts are hobbyists who will buy used gear or repurpose things. That's not a commercial/governmental profile. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
As a test of load, I sent around 650 ntp queries per second (give or take 20 q/s) to the BBB. CPU usage was around 87% idle. There were no dropped packets for the 108,000 sent. Round-trip time was between 287us and 199us. Traffic was around 470kbit/s. Assuming clients have a query rate of 1 per 256s on average, that rate is good for around 150k clients. That also leaves plenty of CPU free for bursts. NTP isn't exactly a heavy protocol :) Is this better or worse than other NTP server platforms? I haven't tested them, so I have no idea. Quoting Chris Albertson albertson.ch...@gmail.com: Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? On Wed, Dec 10, 2014 at 5:58 PM, Dan Drown dan-timen...@drown.org wrote: Quoting Paul tic-...@bodosom.net: Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. As a note to people wanting to use the timer hardware on the BBB - I have a driver for it at https://github.com/ddrown/pps-gmtimer I wrote up the results in using it at http://blog.dan.drown.org/ beaglebone-black-timer-capture-driver/ The summary of it is: pps-gpio - 50% of the time local clock offset within +/- 0.07us, 98% within +/- 0.61us pps-gmtimer - 50% of the time local clock offset within +/- 0.04us, 98% within +/- 0.43us Also, if you're using pps-gpio, you might want to disable cpufreq and force your processor to 1GHz. It'll help with interrupt latency and jitter. cpufreq ondemand, 300MHz-1GHz - http://dan.drown.org/bbb/run9/ interrupt-latency.png 98% of interrupts handled 12.92us-23.21us after the event happened. cpufreq forced 1GHz - http://dan.drown.org/bbb/run8/interrupt-latency.png 98% of interrupts handled 6.04us-8.58us after the event happened. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/11/14, 7:04 AM, Paul wrote: On Thu, Dec 11, 2014 at 9:45 AM, Chris Albertson albertson.ch...@gmail.com wrote: Your logic would disqualify EVERY computer made today. What will still be in production in 10 years? The ones you make yourself. Or if you're a nation-state the ones you have made to your specifications which include N years of support, or the ones you make yourself. Most time-nuts are hobbyists who will buy used gear or repurpose things. That's not a commercial/governmental profile. Most national labs are more like time-nuts hobbyists for many of the same reasons. A big business (think cellphone provider) depreciates and amortizes their gear, so they cycle through in 3-5 years, and *build the update process into the budget*. They also buy in large quantities. National labs are like hobbyists: they buy things and expense them in the year purchased and use them until they fall apart. They have a succession of independent projects which come into existence, then go away, generally without any provision for sustaining engineering. The research is done, the report published, move on. They're doing things in small volumes and repurposing is a way of life. The support is original builder. And as long as it keeps working, things are great. When it stops working, then you're hoping a) the original builder is still working or alive b) that you have a charge number to use Much like a hobbyist. The Z3801 GPSDO in the garage will probably run for a good long time. If my daughter needed the 10 MHz output for a personal project (unlikely, she's a molec bio person) and it failed her options would be: a) Hope I'm alive and interested in fixing it. There's no substantive documentation on the power supply I used (surplus, of course) or the cabling (bare molex pin shoved into the connector on the Z3801) or the RS422-RS232 mod (jumpers inside the box). b) Hope her budget allows buying a replacement and adapting to the replacement, or finding someone willing to fix it. Even for things done in the context of a big mission, there's typically no mechanism for continuing support. You built a nice phase noise test setup to characterize the oscillators for a space radio that's getting put into a Mars rover. You've finished the oscillators and delivered them to the next higher level of integration. Your budget ends. Your test set gets put in a closet, left on a bench, passed on to another project, but whatever the case, there's no funding to improve, maintain, modify, update, etc. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 9:59 AM, Jim Lux jim...@earthlink.net wrote: Linux isn't a whole lot better. If you have a system you cobbled together in 2004 In the PPS via GPIO this is an issue and you don't have to go back 10 years. There's been a major change between (I think) 3.8 and later kernels which makes some things much easier but breaks other things. To be clear my comments aren't about complex and subtle $10k lab instruments. They're specifically about 'my two year old BBB doesn't work like my new one'. NTP servers are readily done as a real appliance. Not a stripped down OS of choice box that is hosting NTPD that someone calls an 'appliance'. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 10:33 AM, Jim Lux jim...@earthlink.net wrote: Most national labs are more like time-nuts hobbyists for many of the same reasons. A big business (think cellphone provider) depreciates and amortizes their gear, so they cycle through in 3-5 years, and *build the update process into the budget*. They also buy in large quantities. I was overly brief. A good example would Windows XP. Support from Microsoft stopped in April or whenever. Except for the people with contracts that said it didn't. And some part of my brain knows that time distribution from NIST (I think NIST not the Navy) is contracted out which presumably pushes all the maintenance problems onto the contractor. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 10:27 AM, Dan Drown dan-timen...@drown.org wrote: Is this better or worse than other NTP server platforms? I haven't tested them, so I have no idea. Tharp says his appliance can sustain thousands of queries per second. Even under high throughput timekeeping operations are never disrupted or perturbed. But enough of that. From the time-nut perspective what's the interest in high resolution NTP? I mean beyond the can I do this? appeal. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/11/14, 7:35 AM, Paul wrote: On Thu, Dec 11, 2014 at 9:59 AM, Jim Lux jim...@earthlink.net wrote: Linux isn't a whole lot better. If you have a system you cobbled together in 2004 In the PPS via GPIO this is an issue and you don't have to go back 10 years. There's been a major change between (I think) 3.8 and later kernels which makes some things much easier but breaks other things. To be clear my comments aren't about complex and subtle $10k lab instruments. They're specifically about 'my two year old BBB doesn't work like my new one'. NTP servers are readily done as a real appliance. Not a stripped down OS of choice box that is hosting NTPD that someone calls an 'appliance'. Maybe that's the key.. think of it as an appliance. If it stops working, and it's not because of something simple (power cord), then you're probably better off building a new one from scratch than trying to fix the old one. That is, the labor involved in port to a new platform might be substantially less than find old platform and install it in old box, if only because things like tool chains tend to follow the latest hardware. Even if you kept the tool chain for your old platform, running it on a new computer might be problematic. (recognizing that there are people out there running IBM 1401 emulators on System/360 emulators on... but that takes time too) Most folks don't try to repair their 20 year old toaster or refrigerator or TV that has non-trivially failed. I'm speaking as someone who just replaced a 17 year old refrigerator. After 2 weeks of diagnosis and small scale fix attempts, the $2000 was painful, but as it happens, the electricity cost of $200-300/yr is a lot more than the $120/yr annualized cost of the refrigerator. The new refrigerator has a *measured* power consumption 1/2 the old one, so if it lasts 15 years (my observed typical refrigerator life expectancy) the lower electrical costs will make up for the expense. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Discussing the lifetime of NTP server hardware is all well and good but given the thrust of this list, i.e. individual time-nuttery, I don't see it as being too germane. Few of us have the same problems that Jim Lux has at JPL. I want to have a good time and frequency source in my little network that I run. I can put an extra BBB or two aside to run NTP. Eventually I will want to replace it but I bet that there will be an adequate SBC and free OS to do that when need arises. So, I am still looking for a straight-forward, here is a really good way to use a BBB coupled to a GPS 1pps to do NTP, treatise. Better still if someone is using their LTE-lite to do it. It seems like a nice little package for the amateur time-nut for everyday time and frequency keeping. Oh, and if it has nixie tubes to display current time, umso besser! After all, I still need to set my old-style watch and a few mechanical chronographs I have kicking around. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 10:03 AM, Paul tic-...@bodosom.net wrote: On Thu, Dec 11, 2014 at 10:27 AM, Dan Drown dan-timen...@drown.org wrote: Is this better or worse than other NTP server platforms? I haven't tested them, so I have no idea. Tharp says his appliance can sustain thousands of queries per second. Even under high throughput timekeeping operations are never disrupted or perturbed. But enough of that. From the time-nut perspective what's the interest in high resolution NTP? I mean beyond the can I do this? appeal. We are all time nuts to one degree or another or we wouldn't be here. I personally want all the clocks in my house, including all the computers (I have about 10 running at any given moment here), to have time resolution better than my ability to perceive errors. (To my eye that is about 100ms for clocks with a sweep second hand.) and in the 1ms-or-better range for the computers. I want to know that, when two things get time-stamped on different machines, I can tell which happened first from the point of view of a DBMS dealing with concurrency issues. So a stratum 1 server in my house that is independent of my external internet connectivity seems desirable. Look, I used to leave WWV running all the time on a receiver. That background D D D was very reassuring as I moved through the house watching the sweep second hands ticking in time with WWV. Time to move forward in true time-nut fashion. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
[] So, I am still looking for a straight-forward, here is a really good way to use a BBB coupled to a GPS 1pps to do NTP, treatise. Better still if someone is using their LTE-lite to do it. It seems like a nice little package for the amateur time-nut for everyday time and frequency keeping. [] Brian Lloyd If it helps, Brian, my notes for doing the same thing with a Raspberry Pi are here: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html Includes a wall-clock but no nixies: http://www.satsignal.eu/raspberry-pi/DigitalClock.html Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Quoting Paul tic-...@bodosom.net: From the time-nut perspective what's the interest in high resolution NTP? I mean beyond the can I do this? appeal. From a practical standpoint, I don't personally have any application that benefits from sub-1s accuracy. I'm just doing it for fun and learning. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/11/14, 8:11 AM, Brian Lloyd wrote: Discussing the lifetime of NTP server hardware is all well and good but given the thrust of this list, i.e. individual time-nuttery, I don't see it as being too germane. Few of us have the same problems that Jim Lux has at JPL. Actually, I think my point was that the problems I face at JPL are essentially identical to the problems we face at home. I'm not in the time and frequency group (and I don't know that they actually are better off.. although they do have rooms full of good clocks), so in our areas, we tend to have little point solutions to problems. It's not like there's a big time/frequency infrastructure with *free* spigots from the maser in every lab. You have to pay for this stuff on your project funds, and a lot of times, it seems easier to find a one time expense (summer hire intern!) than sign up for a perpetual monthly charge plus the infrastructure change cost to pull the fiber/coax. We do have NTP, of course. But network drops are about $30-40/month, so in a lab, you might decide, hey, I can buy a widget for a few hundred dollars, and I'll have a better than NTP time source forever. And if you've got a student hire, buying that $200 unit off eBay or Amazon and taping a GPS antenna to the window starts to look pretty attractive. There's probably more than a 100 (certainly dozens) of little GPS antennas all over the lab connected to a bewildering variety of time/frequency sources in labs. Sure, there's a goodly number of TrueTime/Fluke/Pendulum/Symmetricom boxes of various vintages and models, but there's also all manner of home-grown stuff. Those student projects.. What a great way to get someone in for a few months on a sort of trial basis. They get a really nice senior project and you both get to find out if JPL is the kind of place they'd like to work. I will confess that the only student intern who I had doing a timing related project didn't really become imbued with the true fascination for time and time transfer that I was hoping. On the other hand, it is truly a niche.. people often don't appreciate how important it is, and how widely used it is.) I want to have a good time and frequency source in my little network that I run. I can put an extra BBB or two aside to run NTP. Eventually I will want to replace it but I bet that there will be an adequate SBC and free OS to do that when need arises. Which is exactly what we do at work.. Lots of old PCs doing something, but there's that what do we do when the PC fails question. Just like at home, you've got a limited budget and time available. Do you stock a couple extra BBBs or RPis? That costs money, and you need to have a place to store them where you'll be able to find them. Or do you hope that when it fails 5 years hence, you'll have time and budget to rebuild? So, I am still looking for a straight-forward, here is a really good way to use a BBB coupled to a GPS 1pps to do NTP, treatise. Better still if someone is using their LTE-lite to do it. It seems like a nice little package for the amateur time-nut for everyday time and frequency keeping. Essentially, you want the equivalent of a Microsemi (Symmetricom/TrueTime) XL-GPS with the right options for, say, $500 or less. I do too. But I'm also not under any illusion that when my homegrown unit fails that I'll be able to fix it, or rebuild it for the same price. It will depend on someone having done the redesign using whatever is available then, and published the cookbook. Oh, and if it has nixie tubes to display current time, umso besser! After all, I still need to set my old-style watch and a few mechanical chronographs I have kicking around. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 10:46 AM, Jim Lux jim...@earthlink.net wrote: Actually, I think my point was that the problems I face at JPL are essentially identical to the problems we face at home. I'm not in the time and frequency group (and I don't know that they actually are better off.. although they do have rooms full of good clocks), so in our areas, we tend to have little point solutions to problems. It's not like there's a big time/frequency infrastructure with *free* spigots from the maser in every lab. You have to pay for this stuff on your project funds, and a lot of times, it seems easier to find a one time expense (summer hire intern!) than sign up for a perpetual monthly charge plus the infrastructure change cost to pull the fiber/coax. We do have NTP, of course. But network drops are about $30-40/month, so in a lab, you might decide, hey, I can buy a widget for a few hundred dollars, and I'll have a better than NTP time source forever. And if you've got a student hire, buying that $200 unit off eBay or Amazon and taping a GPS antenna to the window starts to look pretty attractive. There's probably more than a 100 (certainly dozens) of little GPS antennas all over the lab connected to a bewildering variety of time/frequency sources in labs. Sure, there's a goodly number of TrueTime/Fluke/Pendulum/Symmetricom boxes of various vintages and models, but there's also all manner of home-grown stuff. Has anyone there noticed the amount of time and money spent recreating the same thing over and over? Sure, individually it is cheap but when you do the same thing hundreds of times, it is no longer a tiny amount. Clearly it is a common needed service/device that your IT (or whatever) dept could provide for nearly nothing. Sheesh. Which is exactly what we do at work.. Lots of old PCs doing something, but there's that what do we do when the PC fails question. Just like at home, you've got a limited budget and time available. Do you stock a couple extra BBBs or RPis? That costs money, and you need to have a place to store them where you'll be able to find them. Why not? The freakin' things are down to about $35 for an RPi and $55 for a BBB. And the price for this is going to go down again. (Well, eventually fabbing the board and soldering the nearly-free components is going to define the lower bound in price but the performance can't help but increase.) Or do you hope that when it fails 5 years hence, you'll have time and budget to rebuild? And in 5 years there will be equivalent or better hardware at the same price point. Stay in and eat beans for dinner one night to pay for your new NTP server. So, I am still looking for a straight-forward, here is a really good way to use a BBB coupled to a GPS 1pps to do NTP, treatise. Better still if someone is using their LTE-lite to do it. It seems like a nice little package for the amateur time-nut for everyday time and frequency keeping. Essentially, you want the equivalent of a Microsemi (Symmetricom/TrueTime) XL-GPS with the right options for, say, $500 or less. Well, it is looking like I can do this very nicely for about $250 including the BBB or RPi, LTE-Lite, and a 1U rack-box. Yes I have to build a buffer for the 1pps and 10MHz output but that has been covered here very nicely. I do too. But I'm also not under any illusion that when my homegrown unit fails that I'll be able to fix it, or rebuild it for the same price. It will depend on someone having done the redesign using whatever is available then, and published the cookbook. I'm still thinking that the spare RPi or two tucked into the box with the OS already loaded and configured will go a long way toward making sure I can recover and keep going for many years. I have a BBB with Debian running NTP that has been running for about 5 months now without a reboot as just a local NTP stratum-3 server for my local machines. Works pretty well so I am satisfied that it is stable to do the job. Once it is started I don't expect to be doing a lot of OS upgrades. If it only runs NTP and all the other services/daemons are turned off, it is going to be pretty difficult to exploit. If it ain't broke, don't fix it. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 11:11 AM, Brian Lloyd br...@lloyd.aero wrote: So, I am still looking for a straight-forward, here is a really good way to use a BBB coupled to a GPS 1pps to do NTP, treatise Fellow time-nut Dan Drown has done this although he uses Chrony rather than NTPd. The idea is the same but you'd probably have to compile ntpd with PPS support. http://blog.dan.drown.org/beaglebone-black-ntpgps-server/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Brian... Look, I used to leave WWV running all the time on a receiver. That background D D D was very reassuring as I moved through the house watching the sweep second hands ticking in time with WWV. Based on personal experience, this strongly suggests that you weren't married at the time :-). Tom Holmes, N8ZM -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Lloyd Sent: Thursday, December 11, 2014 11:21 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Beaglebone NTP server On Thu, Dec 11, 2014 at 10:03 AM, Paul tic-...@bodosom.net wrote: On Thu, Dec 11, 2014 at 10:27 AM, Dan Drown dan-timen...@drown.org wrote: Is this better or worse than other NTP server platforms? I haven't tested them, so I have no idea. Tharp says his appliance can sustain thousands of queries per second. Even under high throughput timekeeping operations are never disrupted or perturbed. But enough of that. From the time-nut perspective what's the interest in high resolution NTP? I mean beyond the can I do this? appeal. We are all time nuts to one degree or another or we wouldn't be here. I personally want all the clocks in my house, including all the computers (I have about 10 running at any given moment here), to have time resolution better than my ability to perceive errors. (To my eye that is about 100ms for clocks with a sweep second hand.) and in the 1ms-or-better range for the computers. I want to know that, when two things get time-stamped on different machines, I can tell which happened first from the point of view of a DBMS dealing with concurrency issues. So a stratum 1 server in my house that is independent of my external internet connectivity seems desirable. Look, I used to leave WWV running all the time on a receiver. That background D D D was very reassuring as I moved through the house watching the sweep second hands ticking in time with WWV. Time to move forward in true time-nut fashion. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 12/11/14, 9:54 AM, Brian Lloyd wrote: On Thu, Dec 11, 2014 at 10:46 AM, Jim Lux jim...@earthlink.net wrote: Actually, I think my point was that the problems I face at JPL are essentially identical to the problems we face at home. I'm not in the time and frequency group (and I don't know that they actually are better off.. although they do have rooms full of good clocks), so in our areas, we tend to have little point solutions to problems. Has anyone there noticed the amount of time and money spent recreating the same thing over and over? Sure, individually it is cheap but when you do the same thing hundreds of times, it is no longer a tiny amount. Clearly it is a common needed service/device that your IT (or whatever) dept could provide for nearly nothing. Sheesh. Nothing in an institutional environment is provided for nearly nothing. The *actual cost* to provide a network drop is very close to the $30/month my project gets charged (there's armies of auditors checking this stuff). There's also the phenomenon (applicable to hobbyist and business alike) of different kinds of money and resources. As a hobbyist, I pay for hardware, but my time is (sort of) free, at least in the sense that I don't have to write a check to myself for the time I spend. I do pay an opportunity cost in the sense that time I spend stringing coax across my roof to the antenna is time that I can't spend on something else which potentially is remunerative. Similarly, in business, there's a difference between project funds and infrastructure funds. Likewise, a big difference between capital and expenses, and local situations and project stuff might push one one way or another. For NASA, each year stands alone, too, subject to the vagaries of Congress and the Executive Branch: just because you have funding this year does not mean that your project will be funded next year, even if it's a multiyear project. A 50k project isn't going to be able to buy a $100k Vector Network Analyzer; they're going to rent one for a few thousand a month. A $10M project lasting 3 years might say, hey, we'll spend 100k in the first year, rather than 100k spread over 3 years as monthly rental fees. Or, more timenuts-ish.. Do I buy a $5k box from MicroSemi, put it in the rack and go? Do I buy $500 in parts and $1000 in student intern? Do I spend $3000 in facilities costs to run a fiber drop to my lab from the maser, the purchase costs of the local cleanup loop and buffers, and then pay whatever the monthly fee is to keep that fiber alive and my share of the maser cost? (I actually don't know if the maser cost is shared by the users, or paid for by an institutional support account.. But for things like network drops, clean rooms, antenna ranges, ESD inspections, you pay as you use it) It kind of depends on what my needs are. There are relatively few things I might do that need the maser, and I might just drag my test article up the hill to the frequency and timing lab for a few weeks and pay the labor costs of the FTL folks to do it, and for the rest of the time when all I need is reasonably clean quartz oscillator that is disciplined I use my local GPSDO (whether XL-GPS or homebrew). that's why lists like this are so useful.. Homebrew is more common than some might expect in a research lab environment. And there's an undeniable benefit in rolling your own to develop the skill sets. I am MUCH better suited to making the make/buy/rent decision because I've had practical experience getting a GPSDO working, using a truetime box, and hooking up that cleanup loop from Wenzel to the maser spigot, and subsequently trying to make ADEV/Phase noise measurements with all manner of equipment. So some of that do it over and over rather than institutionally provided might be viewed not as paying too much for the ultimate service, but as a training and educational expense. This is particularly important as the folks coming out of school are increasingly specialized (due to the increasing breadth of what might get covered in a EE or CS degree), and many may not know which end of the soldering iron gets hot, just because it's not something they ever had to do. Which is exactly what we do at work.. Lots of old PCs doing something, but there's that what do we do when the PC fails question. Just like at home, you've got a limited budget and time available. Do you stock a couple extra BBBs or RPis? That costs money, and you need to have a place to store them where you'll be able to find them. Why not? The freakin' things are down to about $35 for an RPi and $55 for a BBB. And the price for this is going to go down again. (Well, eventually fabbing the board and soldering the nearly-free components is going to define the lower bound in price but the performance can't help but increase.) But you also need to stock all the other parts, the GPS receiver, etc. So you're really
Re: [time-nuts] Beaglebone NTP server
If there is always a system running, why go with the bbb? I use the file server in the basement fed with 1pps to the non USB serial port from a TBolt in my office. You do have a file server in the basement don't you? :) I suppose it would be an interesting experiment to feed an NTP server with several PPS signals (either simultaneous or offset) to see how it handles it. Or to set up an NTP chorus fed from multiple PPS sources or even a single PPS source to see how they average out. Maybe over the holidays. I really should finish up running the coax for a shared GPS antenna to the basement. Bob PS: As to the buy a second BBB/RPi question, I've taken to buying what I think will be key spare parts for projects and stocking them. Each project gets a shoebox sized storage bin on the shelves in the basement. One part of the shelves is completed projects, the other is in process. It has the added side benefit of telling me when I have too many unfinished projects. :) On Dec 11, 2014, at 11:45, Tom Holmes thol...@woh.rr.com wrote: Brian... Look, I used to leave WWV running all the time on a receiver. That background D D D was very reassuring as I moved through the house watching the sweep second hands ticking in time with WWV. Based on personal experience, this strongly suggests that you weren't married at the time :-). Tom Holmes, N8ZM -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Lloyd Sent: Thursday, December 11, 2014 11:21 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Beaglebone NTP server On Thu, Dec 11, 2014 at 10:03 AM, Paul tic-...@bodosom.net wrote: On Thu, Dec 11, 2014 at 10:27 AM, Dan Drown dan-timen...@drown.org wrote: Is this better or worse than other NTP server platforms? I haven't tested them, so I have no idea. Tharp says his appliance can sustain thousands of queries per second. Even under high throughput timekeeping operations are never disrupted or perturbed. But enough of that. From the time-nut perspective what's the interest in high resolution NTP? I mean beyond the can I do this? appeal. We are all time nuts to one degree or another or we wouldn't be here. I personally want all the clocks in my house, including all the computers (I have about 10 running at any given moment here), to have time resolution better than my ability to perceive errors. (To my eye that is about 100ms for clocks with a sweep second hand.) and in the 1ms-or-better range for the computers. I want to know that, when two things get time-stamped on different machines, I can tell which happened first from the point of view of a DBMS dealing with concurrency issues. So a stratum 1 server in my house that is independent of my external internet connectivity seems desirable. Look, I used to leave WWV running all the time on a receiver. That background D D D was very reassuring as I moved through the house watching the sweep second hands ticking in time with WWV. Time to move forward in true time-nut fashion. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Dec 11, 2014 at 1:22 PM, Bob Bownes bow...@gmail.com wrote: If there is always a system running, why go with the bbb? I use the file server in the basement fed with 1pps to the non USB serial port from a TBolt in my office. You do have a file server in the basement don't you? :) Yes, I do. Two in fact. They are two of the machines running 7x24 on the network. Unfortunately I have found that NTP on them does not perform well. So being able to throw a $55 board at the problem of optimizing NTP performance and decoupling it from the up/down status of anything else on the network makes sense to me. I consider routing, DNS, and NTP to be services of the network infrastructure and should be independent of anything else. I suppose it would be an interesting experiment to feed an NTP server with several PPS signals (either simultaneous or offset) to see how it handles it. Or to set up an NTP chorus fed from multiple PPS sources or even a single PPS source to see how they average out. Maybe over the holidays. I really should finish up running the coax for a shared GPS antenna to the basement. That does make sense to me. Bob PS: As to the buy a second BBB/RPi question, I've taken to buying what I think will be key spare parts for projects and stocking them. Each project gets a shoebox sized storage bin on the shelves in the basement. One part of the shelves is completed projects, the other is in process. It has the added side benefit of telling me when I have too many unfinished projects. :) That makes sense to me too. As for the 1U time and frequency server, there is a LOT of extra space in the 1U box for an extra BBB and, potentially, for another LTE-lite. Of course, the NTP function will work with just a generic GPS module with 1pps out. Said: are you going to be doing another run of LTE-lite eval boards? I think I would like to get one as a spare. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
br...@lloyd.aero said: I want to have a good time and frequency source in my little network that I run. ... Oh, and if it has nixie tubes to display current time, umso besser! After all, I still need to set my old-style watch and a few mechanical chronographs I have kicking around. xclock -update 1 -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
jim...@earthlink.net said: Ah, but will the exact same single board computer be available for replacement in 5 years? Or will it be Rev F instead of Rev B, with just a few tweaks to improve performance, but also enough that it's not drop the image on it and run What about 10 years? 15? My straw man is to buy a bunch now and put them on the shelf until you need them? It would be interesting to read a good B-school type report on that topic. Is it realistic to expect any electronics related stuff to be available for 10 years? I think I've seen a few boards marked long-lifetime. I don't remember the details. At least one OS distro has a version marked long-lifetime, but I don't know how long that covers. What does the military do for this problem? What's the average lifetime of something like a radio in a military plane? How often do they get upgraded because the old ones are no longer maintainable due to unavailability of parts? What's the average lifetime of a fab line? Or even the max lifetime? (in case you are a big vendor with multiple fab lines for a particular technology) What's the typical lifetime of parts used in timing related gear? Maybe that's the key.. think of it as an appliance. If it stops working, and it's not because of something simple (power cord), then you're probably better off building a new one from scratch than trying to fix the old one. That is, the labor involved in port to a new platform might be substantially less than find old platform and install it in old box, if only because things like tool chains tend to follow the latest hardware. A lot of that depends on the quality of the documentation you kept when you set things up. I've worked with guys who were good at making a big pile of kludgy gear jump through hoops. One of them was very good at writing down what he did. It doesn't have to be a fancy document blessed by 43 proofreaders, but it really helps to mention all the critical steps and/or explain the non-obvious reasons for doing things. I've gotten into the habit of making a checklist of what I have to do to install distro-X from CD and fix it up to do what I want. Every now and then, I want another box just like that one except... It isn't fancy, but it does have a line to remind me about each file that needs editing and what tools are used to set things up. Often there are chunks of code I can cut-paste. Even if you kept the tool chain for your old platform, running it on a new computer might be problematic. (recognizing that there are people out there running IBM 1401 emulators on System/360 emulators on... but that takes time too) It's not uncommon to archive the PC that has all the tools when a significant hardware project is released. Just put a big note on it and push it into a closet in case you ever need it again. (Setting up CAD tools is often quirky and hard to debug.) Again, this needs documentation. Suppose you want to make a simple one line change to fix a typo. What do you do to turn the crank and make the files you hand off to the next step? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi David, Yes, You mean the hourly dips? That is caused by the the VLF receive software that is running on the same PI. It makes hourly recordings of DC to 24 Khz with a USB soundcard. The CPU is running at max capacity most of the time. Perhaps it is now time for a dedicated PI, that only has the task of playing Stratum One. If anyone is interested: https://pivlf.wordpress.com/ 73, Frits W1FVB = Yes, that is quite interesting, Frits, and of course the hourly dips are just as you say. I take it that the spectrum is from a broadband antenna, and that the graphs below are signal strengths of specific stations? Perhaps you have a description of the project. Perhaps link that description from the text: Raspberry PI Project by W1FVB RPi cards have a way of proliferating - I have seven now! At least two are actually doing something useful (ADS-B receiver with a DVB-T dongle, and a wall clock driven by NTP). 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Graham make sure you read up on dtb and fdt. Many if not most distros don't have what you might call a default. On Tuesday, December 9, 2014, Graham / KE9H ke9h.gra...@gmail.com wrote: Dan: Thanks. I don't know where you were quoting from, but it was the answer I needed. Paul: I found BB-BONE-GPS-00A0.dts, so I will start editing/hacking from there. I plan to run under Debian 7.7 or 8-Testing. Thanks, --- Graham == On Tue, Dec 9, 2014 at 5:33 PM, Paul tic-...@bodosom.net javascript:; wrote: On Tue, Dec 9, 2014 at 12:59 PM, Graham / KE9H ke9h.gra...@gmail.com javascript:; wrote: I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. The provided-with-stock-dtb pin is: 0x40 which is P9 pin 15. I use the only free pin on P8 or P9: 0x7c which is P8 pin 26 There are various maps/charts/lists around with the pins. Just decompile /lib/firmware/BB-BONE-GPS-00A0.dtbo and fiddle if you want a different pin. The Debian relases come with dtc, I don't know about Angstrom. e.g. http://www.embedded-things.com/bbb/beaglebone-black-pin-mux-spreadsheet/ ___ time-nuts mailing list -- time-nuts@febo.com javascript:; To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com javascript:; To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Sun, Dec 7, 2014 at 3:10 PM, folkert folk...@vanheusden.com wrote: Regarding the fs error As an aside: this thread is like a zombie. Folkert's reply was to my post from March 2014 in response to Henry Hallam who was replying to a message from Gabs Ricalde posted in June 2013. I suppose I should have waited six months to post this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Well, I am hoping to get to the point where the path to using the BBB as an NTP server using the PRU for more precise timing, and using the LTE-lite to provide the 1pps and time data. Of course, the LTE-lite can also provide 1pps and 10MHz to my workbench. (It's all going to go in a 1U box in the rack next to my workbench.) Yes, I know that all the information is out there and much if it can be gleaned from this list by following several threads back through several months. But that brings to mind playing Adventure. Has anyone compiled a how-to for turning a BBB into an NTP server using the PRU for timing? Seems like a straight-forward and useful turn-key kind of thing. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Neil Schroeder wrote: Graham make sure you read up on dtb and fdt. Many if not most distros don't have what you might call a default. I have done several device tree overlays on the BBB, so I think I can usually get the I/O lines and pin-mux to do what I want them to do. It was a total pain figuring it out without good documentation. Any distro that I use does contain the cape manager, so I have a starting point. == David wrote: RPi cards have a way of proliferating - I have seven now! At least two are actually doing something useful. When you get 24 of them, you can build a parallel super computing cluster. :-) http://www.amazon.com/gp/product/1783989440/ --- Graham == On Wed, Dec 10, 2014 at 10:56 AM, Paul tic-...@bodosom.net wrote: On Sun, Dec 7, 2014 at 3:10 PM, folkert folk...@vanheusden.com wrote: Regarding the fs error As an aside: this thread is like a zombie. Folkert's reply was to my post from March 2014 in response to Henry Hallam who was replying to a message from Gabs Ricalde posted in June 2013. I suppose I should have waited six months to post this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Brian, Sorry about the long post. I was on a similar path recently. I wanted to create a nice and simple Stratum 1 server using a beagleboard. In addition, I wanted to create a nice case for it so I would enjoy looking at it from my desk. Since I was already using a GPS Motorola receiver to create a Linux NTP server, I was pretty sure I had most of the parts. Since The Beagleboard is using systemd I figured I would start by creating a CentOS 7 Stratum 1 machine so I can figure out all the systemd pieces. I finished this 5 days ago. Next, using Cadence Allegro (OrCAD) I designed a proto cape for the Beagleboard. This is also done. I figure I will use the proto cape as a prototype board and also get familiar with all the pins on the Beagleboard I/O headers. This is also done (mostly) as of yesterday. Actually, I was in the middle of documenting this when this thread caught my eye. You and everyone on this list are welcome to the Cadence Project and all the files. You can use this basic project to design any cape for the Beagleboard. I am releasing it as free. Just mention my company: Maxima Physics. I will finish the documentation for CentOS 7 + NTP server over the next few days. I have also been fighting a nasty flu :( Comments are most welcome. -George Hrysanthopoulos On 12/10/2014 04:58 PM, Brian Lloyd wrote: Well, I am hoping to get to the point where the path to using the BBB as an NTP server using the PRU for more precise timing, and using the LTE-lite to provide the 1pps and time data. Of course, the LTE-lite can also provide 1pps and 10MHz to my workbench. (It's all going to go in a 1U box in the rack next to my workbench.) Yes, I know that all the information is out there and much if it can be gleaned from this list by following several threads back through several months. But that brings to mind playing Adventure. Has anyone compiled a how-to for turning a BBB into an NTP server using the PRU for timing? Seems like a straight-forward and useful turn-key kind of thing. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Dec 10, 2014 at 9:58 PM, Brian Lloyd br...@lloyd.aero wrote: Well, I am hoping to get to the point where the path to using the BBB as an NTP server using the PRU for more precise timing, and using the LTE-lite to provide the 1pps and time data. Of course, the LTE-lite can also provide 1pps and 10MHz to my workbench. (It's all going to go in a 1U box in the rack next to my workbench.) Yes, I know that all the information is out there and much if it can be gleaned from this list by following several threads back through several months. But that brings to mind playing Adventure. Has anyone compiled a how-to for turning a BBB into an NTP server using the PRU for timing? Seems like a straight-forward and useful turn-key kind of thing. Getting a BBB to take 10MHz refclk input (in the fashion of http://www.febo.com/pages/soekris/) and being able to timestamp _multiple_ PPS signals via the PRUs would make for a pretty awesome time-nuts toy. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Dec 10, 2014 at 4:58 PM, Brian Lloyd br...@lloyd.aero wrote: Well, I am hoping to get to the point where the path to using the BBB as an NTP server using the PRU for more precise timing Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. Naturally if you're doing significant computing (heh) on the BBB you might want to use a real time unit. The current portion of this thread is part of the June-2013 hread started by Gabs Ricalde about using TIMER4 for capture with 10MHz/1PPS input. https://www.febo.com/pipermail/time-nuts/2013-June/077430.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Quoting Paul tic-...@bodosom.net: Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. As a note to people wanting to use the timer hardware on the BBB - I have a driver for it at https://github.com/ddrown/pps-gmtimer I wrote up the results in using it at http://blog.dan.drown.org/beaglebone-black-timer-capture-driver/ The summary of it is: pps-gpio - 50% of the time local clock offset within +/- 0.07us, 98% within +/- 0.61us pps-gmtimer - 50% of the time local clock offset within +/- 0.04us, 98% within +/- 0.43us Also, if you're using pps-gpio, you might want to disable cpufreq and force your processor to 1GHz. It'll help with interrupt latency and jitter. cpufreq ondemand, 300MHz-1GHz - http://dan.drown.org/bbb/run9/interrupt-latency.png 98% of interrupts handled 12.92us-23.21us after the event happened. cpufreq forced 1GHz - http://dan.drown.org/bbb/run8/interrupt-latency.png 98% of interrupts handled 6.04us-8.58us after the event happened. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Dan: When you forced/locked the CPU frequency at 1 GHz, did you by any chance measure what it did to the CPU case/package temperature? Or current drain? I note that you used BBB pin P8.7 for PPS input. That allowed you to use it for either pps-gpio or TIMER4 pps-gmtimer, by just changing the pin-mux? --- Graham == On Wed, Dec 10, 2014 at 7:58 PM, Dan Drown dan-timen...@drown.org wrote: Quoting Paul tic-...@bodosom.net: Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. As a note to people wanting to use the timer hardware on the BBB - I have a driver for it at https://github.com/ddrown/pps-gmtimer I wrote up the results in using it at http://blog.dan.drown.org/ beaglebone-black-timer-capture-driver/ The summary of it is: pps-gpio - 50% of the time local clock offset within +/- 0.07us, 98% within +/- 0.61us pps-gmtimer - 50% of the time local clock offset within +/- 0.04us, 98% within +/- 0.43us Also, if you're using pps-gpio, you might want to disable cpufreq and force your processor to 1GHz. It'll help with interrupt latency and jitter. cpufreq ondemand, 300MHz-1GHz - http://dan.drown.org/bbb/run9/ interrupt-latency.png 98% of interrupts handled 12.92us-23.21us after the event happened. cpufreq forced 1GHz - http://dan.drown.org/bbb/run8/interrupt-latency.png 98% of interrupts handled 6.04us-8.58us after the event happened. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? On Wed, Dec 10, 2014 at 5:58 PM, Dan Drown dan-timen...@drown.org wrote: Quoting Paul tic-...@bodosom.net: Using a PRU seems like overkill if all you want from the BBB is NTP. The standard pps-gpio should move the system clock precision below system/network jitter (.5 to 1 microsecond). The next step is using a timer (TIMER4) which should get you into .1 microsecond offsets. As a note to people wanting to use the timer hardware on the BBB - I have a driver for it at https://github.com/ddrown/pps-gmtimer I wrote up the results in using it at http://blog.dan.drown.org/ beaglebone-black-timer-capture-driver/ The summary of it is: pps-gpio - 50% of the time local clock offset within +/- 0.07us, 98% within +/- 0.61us pps-gmtimer - 50% of the time local clock offset within +/- 0.04us, 98% within +/- 0.43us Also, if you're using pps-gpio, you might want to disable cpufreq and force your processor to 1GHz. It'll help with interrupt latency and jitter. cpufreq ondemand, 300MHz-1GHz - http://dan.drown.org/bbb/run9/ interrupt-latency.png 98% of interrupts handled 12.92us-23.21us after the event happened. cpufreq forced 1GHz - http://dan.drown.org/bbb/run8/interrupt-latency.png 98% of interrupts handled 6.04us-8.58us after the event happened. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hello Try to run ntpd with realtime priority (options '-N' or '-P priority'). Your an hourly jobs can be executed several slower but it may improve the time synchronization. 2014-12-09 23:45 GMT+04:00, Frister fris...@gmx.net: Hi David, Yes, You mean the hourly dips? That is caused by the the VLF receive software that is running on the same PI. It makes hourly recordings of DC to 24 Khz with a USB soundcard. The CPU is running at max capacity most of the time. Perhaps it is now time for a dedicated PI, that only has the task of playing Stratum One. If anyone is interested: https://pivlf.wordpress.com/ 73, Frits W1FVB On 12/9/14, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- vbradio.wordpress.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Dec 10, 2014 at 10:21 PM, Michael Tatarinov kuk...@gmail.com wrote: Hello Try to run ntpd with realtime priority (options '-N' or '-P priority'). Your an hourly jobs can be executed several slower but it may improve the time synchronization. And given the price, why try to run multiple, time-critical applications on one BBB or RPi? Just get lots of them. -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Dec 10, 2014 at 10:15 PM, Chris Albertson albertson.ch...@gmail.com wrote: Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? When I think of what we have been using to run NTP down through the years, this is almost funny. The BBB is little in physical package size only. Its processing power is not inconsequential. Fuzzballs anyone? -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Le 11 déc. 2014 à 05:47, Brian Lloyd br...@lloyd.aero a écrit : On Wed, Dec 10, 2014 at 10:15 PM, Chris Albertson albertson.ch...@gmail.com wrote: Those sub 1 u-second numbers are very good. They argue for using the BBB as an NTP server but I wonder if it really is the best. I think the numbers that matter are measures of the close on the computers who use your BBB as a server. In other words the goal is to synchronize a set of computers. Can The little BBB push accurate time out to a set of user computers and keep then in sync better then some other NTP server platform? When I think of what we have been using to run NTP down through the years, this is almost funny. The BBB is little in physical package size only. Its processing power is not inconsequential. The question for anyone using them for other than personal use may be long term reliability. My three Soekris 4501s all died from power supply failiurs after 5 years contnuous use, while the 4801s have 6 years under the belt and still going strong. Will the RPIs and BBBs systematic issues or still be running after the same time? Of course 5 years is not that bad when S1 NTP servers are dedicated to that. Also the cost is so low that replacement isn’t a problem. A no brainer really. Fuzzballs anyone? -- Brian Lloyd Lloyd Aviation 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.aero +1.210.802-8FLY (1.210.802-8359) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
2014-12-11 8:48 GMT+04:00, Brian Lloyd br...@lloyd.aero: On Wed, Dec 10, 2014 at 10:21 PM, Michael Tatarinov kuk...@gmail.com wrote: Hello Try to run ntpd with realtime priority (options '-N' or '-P priority'). Your an hourly jobs can be executed several slower but it may improve the time synchronization. And given the price, why try to run multiple, time-critical applications on one BBB or RPi? Just get lots of them. I think an hourly jobs isn't time-critical and must have a low priority. Why a lots if one (with tuning) is enough? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB On 12/8/14, David J Taylor david-tay...@blueyonder.co.uk wrote: From: Chris Albertson Really? The PPS to GPIO interface is handles in user space? It is not interrupt driven? In the implementations I've seen the critical real time work is done inside the PPS interrupt handler and then of course ntpd runs in userland and can take as much time as it needs = Folkert's solution was very helpful, but there is now kernel-mode PPS support for a GPIO pin the current Raspberry Pi Linux - see: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#easy I'm running that on a couple of systems here. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- vbradio.wordpress.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hourly cron jobs, perhaps? -Bob On Tue, Dec 9, 2014 at 8:04 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
For those of you that have gotten the BeagleBone Black up and running as an ntp server with the 1PPS signal input in kernel space, what gpio input pin is being used? I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. Thanks, --- Graham / KE9H == On Tue, Dec 9, 2014 at 11:18 AM, Bob Darlington rdarling...@gmail.com wrote: Hourly cron jobs, perhaps? -Bob On Tue, Dec 9, 2014 at 8:04 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
If you're using the pps-gpio module, the hardware can support up to Two Interrupt Inputs per Bank. So if you're not using the gpio for anything else, any of the gpio should work. If you want to use the timer hardware (and pps-dmtimer module), each timer has an assigned pin. Quoting Graham / KE9H ke9h.gra...@gmail.com: For those of you that have gotten the BeagleBone Black up and running as an ntp server with the 1PPS signal input in kernel space, what gpio input pin is being used? I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. Thanks, --- Graham / KE9H == On Tue, Dec 9, 2014 at 11:18 AM, Bob Darlington rdarling...@gmail.com wrote: Hourly cron jobs, perhaps? -Bob On Tue, Dec 9, 2014 at 8:04 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Tue, Dec 9, 2014 at 12:59 PM, Graham / KE9H ke9h.gra...@gmail.com wrote: I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. The provided-with-stock-dtb pin is: 0x40 which is P9 pin 15. I use the only free pin on P8 or P9: 0x7c which is P8 pin 26 There are various maps/charts/lists around with the pins. Just decompile /lib/firmware/BB-BONE-GPS-00A0.dtbo and fiddle if you want a different pin. The Debian relases come with dtc, I don't know about Angstrom. e.g. http://www.embedded-things.com/bbb/beaglebone-black-pin-mux-spreadsheet/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi David, Yes, You mean the hourly dips? That is caused by the the VLF receive software that is running on the same PI. It makes hourly recordings of DC to 24 Khz with a USB soundcard. The CPU is running at max capacity most of the time. Perhaps it is now time for a dedicated PI, that only has the task of playing Stratum One. If anyone is interested: https://pivlf.wordpress.com/ 73, Frits W1FVB On 12/9/14, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel was holding me back. I followed your instructions and everything works beautiful. The PI that is running the PPS timekeeping with NTP is serving as a VLF receiver as well. Taxing the poor CPU, but with kernel PPS support the NTP daemon has become way happier! (see attachment) 73, Frits W1FVB == Oh, yes! That's much better, Frits! Delighted to have helped! (Although it now shows up an hourly periodicity - any idea what might be causing that?) 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- vbradio.wordpress.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Dan: Thanks. I don't know where you were quoting from, but it was the answer I needed. Paul: I found BB-BONE-GPS-00A0.dts, so I will start editing/hacking from there. I plan to run under Debian 7.7 or 8-Testing. Thanks, --- Graham == On Tue, Dec 9, 2014 at 5:33 PM, Paul tic-...@bodosom.net wrote: On Tue, Dec 9, 2014 at 12:59 PM, Graham / KE9H ke9h.gra...@gmail.com wrote: I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. The provided-with-stock-dtb pin is: 0x40 which is P9 pin 15. I use the only free pin on P8 or P9: 0x7c which is P8 pin 26 There are various maps/charts/lists around with the pins. Just decompile /lib/firmware/BB-BONE-GPS-00A0.dtbo and fiddle if you want a different pin. The Debian relases come with dtc, I don't know about Angstrom. e.g. http://www.embedded-things.com/bbb/beaglebone-black-pin-mux-spreadsheet/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
It can be but suffers from enough jitter to be unusable. All current BBB out of the box kernels have PPS-gpio. Google PPS gpio DTS bbb. Enjoy :-) On Sunday, December 7, 2014, Chris Albertson albertson.ch...@gmail.com wrote: On Sun, Dec 7, 2014 at 12:09 PM, folkert folk...@vanheusden.com javascript:; wrote: On my rpi the jitter is between 2 and 10us iirc but it is a while since I tested it. A quick peak shows me currently 3us jitter. Not bad for a userspace solution imho. Really? The PPS to GPIO interface is handles in user space? It is not interrupt driven? In the implementations I've seen the critical real time work is done inside the PPS interrupt handler and then of course ntpd runs in userland and can take as much time as it needs -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com javascript:; To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
I prefer the Beaglebone to the Pi because of the silly USB glitch but out of three BBBs only one will run for more than a month without wedging. This may be because I run Debian but as with the Pi USB bug it's not much comfort when the box fails. The Pi I use as an NTP server ran for 4 months and developed a filesystem error. It's been up two months post-repair. If I depended on a server built around a dev board I'd be careful to make the SDcard/eMMC read-only and build more than one. Regarding the fs error: consider replacing ext3 for f2fs. F2fs does software wear leveling. Folkert van Heusden -- Nagios user? Check out CoffeeSaint - the versatile Nagios status viewer! http://www.vanheusden.com/java/CoffeeSaint/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) Actually, I was thinking of doing exactly the same thing. I am interested in any answers for this too. If compiling a kernel is required and too daunting, then there's rpi_gpio_ntp: http://www.vanheusden.com/time/rpi_gpio_ntp/ Initially only for raspberry pi but I noticed I made it generic enough to work on all linux systems with pps via gpio. On my rpi the jitter is between 2 and 10us iirc but it is a while since I tested it. A quick peak shows me currently 3us jitter. Not bad for a userspace solution imho. Folkert van Heusden -- MultiTail è uno flexible tool per seguire di logfiles e effettuazione di commissioni. Feltrare, provedere da colore, merge, 'diff-view', etc. http://www.vanheusden.com/multitail/ -- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Sun, Dec 7, 2014 at 12:09 PM, folkert folk...@vanheusden.com wrote: On my rpi the jitter is between 2 and 10us iirc but it is a while since I tested it. A quick peak shows me currently 3us jitter. Not bad for a userspace solution imho. Really? The PPS to GPIO interface is handles in user space? It is not interrupt driven? In the implementations I've seen the critical real time work is done inside the PPS interrupt handler and then of course ntpd runs in userland and can take as much time as it needs -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
From: Chris Albertson Really? The PPS to GPIO interface is handles in user space? It is not interrupt driven? In the implementations I've seen the critical real time work is done inside the PPS interrupt handler and then of course ntpd runs in userland and can take as much time as it needs = Folkert's solution was very helpful, but there is now kernel-mode PPS support for a GPIO pin the current Raspberry Pi Linux - see: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#easy I'm running that on a couple of systems here. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 5:51 PM, Henry Hallam he...@pericynthion.org wrote: I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) I've managed (almost by accident) to run my dev boards and related GPS off the same power until this one. In the BBB instance having two power supplies added a fatal level of noise to GPIO input. On Thu, Mar 27, 2014 at 12:01 AM, nuts n...@lazygranch.com wrote: Much appreciated. I have that GPS. Turns out this thread points out an issue which will need to checked: https://groups.google.com/forum/#!msg/beagleboard/emMCqt_mllI/bf7jL_ahPjYJ I'm currently not able to simultaneously read the serial output and the PPS. Some minor issue I'm sure. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) Cheers, Henry = Henry. Maybe my notes using Linux on the Raspberry Pi might help? http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 26/03/14 23:18, Brian Lloyd wrote: Well, yeah. I figured that I would run the 1pps from my T-bolt to a GPIO line with appropriate clamping to 3.3V. But if anyone has done this before and run into anything of note, that would be nice to know ahead of time. Can I suggest you consider FreeBSD ? You can use the TIMER4-7 input pins as PPS input for a better PPS. See the following URL for details: http://lists.freebsd.org/pipermail/freebsd-arm/2013-February/004769.html If I recall correctly, the patch is in the FreeBSD 10 snapshots for the Beaglebone, so you don't need to apply it, but you will need to enable PPS and ensure one of the four TIMER pins is set to input in the DTS and recompile. Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hello all, School's about to end so I can finally work on this. I think there is a standard GPIO PPS driver, configured using the device tree but I haven't tried that. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
You know, we have two threads going on here for both GPSDOs and NTP servers. Frankly, the device I want in my shack is a box that does both. I would love to have a BBB be an NTP server but also discipline an OCXO. I would like it to have a nice distribution amp as well for the 10MHz reference signal. Lastly, it should probably have a really cool Nixie tube display of UTC. (OK, LCD is cheaper but not nearly as cool. Maybe big, bright, 7-segment LED displays?) -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Thanks for all the hints everyone. Lots to try! Henry On Thu, Mar 27, 2014 at 2:41 AM, Iain Young i...@g7iii.net wrote: On 26/03/14 23:18, Brian Lloyd wrote: Well, yeah. I figured that I would run the 1pps from my T-bolt to a GPIO line with appropriate clamping to 3.3V. But if anyone has done this before and run into anything of note, that would be nice to know ahead of time. Can I suggest you consider FreeBSD ? You can use the TIMER4-7 input pins as PPS input for a better PPS. See the following URL for details: http://lists.freebsd.org/pipermail/freebsd-arm/2013-February/004769.html If I recall correctly, the patch is in the FreeBSD 10 snapshots for the Beaglebone, so you don't need to apply it, but you will need to enable PPS and ensure one of the four TIMER pins is set to input in the DTS and recompile. Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) Cheers, Henry On Thu, Jun 20, 2013 at 7:37 PM, Gabs Ricalde gsrica...@gmail.com wrote: On Thu, Jun 20, 2013 at 3:39 AM, Chris Howard ch...@elfpen.com wrote: Are you using the original BeagleBone or the new BeagleBone Black? I'm using the original BeagleBone. it should work on the BeagleBone Black. Will you have any details available about what parts are needed to set it up? If your GPS receiver is using 3.3V logic, wiring it up is straightforward, similar to the Raspberry Pi NTP server. I will probably setup a page describing this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi The quick / dirty / easy way for any of the NTP stuff with a GPSDO is to simply run the PPS in. PPS into serial is one way, pps into a GPIO is another way. Bob On Mar 26, 2014, at 5:51 PM, Henry Hallam he...@pericynthion.org wrote: Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) Cheers, Henry On Thu, Jun 20, 2013 at 7:37 PM, Gabs Ricalde gsrica...@gmail.com wrote: On Thu, Jun 20, 2013 at 3:39 AM, Chris Howard ch...@elfpen.com wrote: Are you using the original BeagleBone or the new BeagleBone Black? I'm using the original BeagleBone. it should work on the BeagleBone Black. Will you have any details available about what parts are needed to set it up? If your GPS receiver is using 3.3V logic, wiring it up is straightforward, similar to the Raspberry Pi NTP server. I will probably setup a page describing this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 4:51 PM, Henry Hallam he...@pericynthion.orgwrote: Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) Actually, I was thinking of doing exactly the same thing. I am interested in any answers for this too. -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 5:05 PM, Bob Camp li...@rtty.us wrote: Hi The quick / dirty / easy way for any of the NTP stuff with a GPSDO is to simply run the PPS in. PPS into serial is one way, pps into a GPIO is another way. Well, yeah. I figured that I would run the 1pps from my T-bolt to a GPIO line with appropriate clamping to 3.3V. But if anyone has done this before and run into anything of note, that would be nice to know ahead of time. -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Hi With a GPIO pulse width should not be an issue. With RS-232 you might have needed a pulse stretcher. Bob On Mar 26, 2014, at 7:18 PM, Brian Lloyd br...@lloyd.com wrote: On Wed, Mar 26, 2014 at 5:05 PM, Bob Camp li...@rtty.us wrote: Hi The quick / dirty / easy way for any of the NTP stuff with a GPSDO is to simply run the PPS in. PPS into serial is one way, pps into a GPIO is another way. Well, yeah. I figured that I would run the 1pps from my T-bolt to a GPIO line with appropriate clamping to 3.3V. But if anyone has done this before and run into anything of note, that would be nice to know ahead of time. -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 2:51 PM, Henry Hallam he...@pericynthion.orgwrote: Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) It's best to go in steps. Resist the temptation to simply connect everything, turn it on and see it is works. The first step is to get NTP installed and running using Internet pool servers for reference clocks. Make sure this is working reliably. NTP may already be mostly configured. I don't know. Next make sure the kernel level PPS diver is working. To test PPS there is a user-land test program you can run that simply prints the time of each pulse to the console. Besure to watch both the voltage levels (the Beagle is 3.3 volts) and the polarity of the pulse. If you get the polarity wrong it will appear t work but the timing will lag by the pulse width (because the falling edge is now the raising edge.) Be sure and match up the levels for both serial and PPS. After both of the above, adding a GPS based reference clock to NTP is easy. All you do is edit the config file. Obviously I've left out much detail but the biggest thing is to follow the step by step process -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, 26 Mar 2014 17:40:07 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Mar 26, 2014 at 2:51 PM, Henry Hallam he...@pericynthion.orgwrote: Hi Gabs, I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) It's best to go in steps. Resist the temptation to simply connect everything, turn it on and see it is works. The first step is to get NTP installed and running using Internet pool servers for reference clocks. Make sure this is working reliably. NTP may already be mostly configured. I don't know. Next make sure the kernel level PPS diver is working. To test PPS there is a user-land test program you can run that simply prints the time of each pulse to the console. Besure to watch both the voltage levels (the Beagle is 3.3 volts) and the polarity of the pulse. If you get the polarity wrong it will appear t work but the timing will lag by the pulse width (because the falling edge is now the raising edge.) Be sure and match up the levels for both serial and PPS. After both of the above, adding a GPS based reference clock to NTP is easy. All you do is edit the config file. Obviously I've left out much detail but the biggest thing is to follow the step by step process Job number one on the Beaglebone Black (and I assume the regular version) is to install NTP. Otherwise it doesn't even know the date. It has no battery for RTC. Beyond that, I haven't found a very clear way to get the gpio-pps going. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 7:17 PM, Bob Camp li...@rtty.usjavascript:_e(%7B%7D,'cvml','li...@rtty.us'); wrote: Hi With a GPIO pulse width should not be an issue. With RS-232 you might have needed a pulse stretcher. That is what I was thinking as well. Any suggestions on software issues in getting this running? -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com javascript:_e(%7B%7D,'cvml','br...@lloyd.com'); +1.916.877.5067 -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Wed, Mar 26, 2014 at 5:51 PM, Henry Hallam he...@pericynthion.orgwrote: I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Here's an example for the Black. I believe the same ideas apply to the Beaglebone (White). http://the8thlayerof.net/2013/12/08/adafruit-ultimate-gps-cape-creating-custom-beaglebone-black-device-tree-overlay-file/ I prefer the Beaglebone to the Pi because of the silly USB glitch but out of three BBBs only one will run for more than a month without wedging. This may be because I run Debian but as with the Pi USB bug it's not much comfort when the box fails. The Pi I use as an NTP server ran for 4 months and developed a filesystem error. It's been up two months post-repair. If I depended on a server built around a dev board I'd be careful to make the SDcard/eMMC read-only and build more than one. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Much appreciated. I have that GPS. It didn't occur to me to build my own cape. Had I known, I would have ordered that board had I seen this webspage. I can probably cut some out of perf board. On Wed, 26 Mar 2014 21:37:43 -0400 Paul tic-...@bodosom.net wrote: On Wed, Mar 26, 2014 at 5:51 PM, Henry Hallam he...@pericynthion.orgwrote: I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Here's an example for the Black. I believe the same ideas apply to the Beaglebone (White). http://the8thlayerof.net/2013/12/08/adafruit-ultimate-gps-cape-creating-custom-beaglebone-black-device-tree-overlay-file/ I prefer the Beaglebone to the Pi because of the silly USB glitch but out of three BBBs only one will run for more than a month without wedging. This may be because I run Debian but as with the Pi USB bug it's not much comfort when the box fails. The Pi I use as an NTP server ran for 4 months and developed a filesystem error. It's been up two months post-repair. If I depended on a server built around a dev board I'd be careful to make the SDcard/eMMC read-only and build more than one. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
I have a practical application for this, I'm anxious to see your web page on how to do it. Thanks. -- eric On Thu, Jun 20, 2013 at 12:37 PM, Gabs Ricalde gsrica...@gmail.com wrote: On Thu, Jun 20, 2013 at 3:39 AM, Chris Howard ch...@elfpen.com wrote: Are you using the original BeagleBone or the new BeagleBone Black? I'm using the original BeagleBone. it should work on the BeagleBone Black. Will you have any details available about what parts are needed to set it up? If your GPS receiver is using 3.3V logic, wiring it up is straightforward, similar to the Raspberry Pi NTP server. I will probably setup a page describing this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Thu, Jun 20, 2013 at 3:39 AM, Chris Howard ch...@elfpen.com wrote: Are you using the original BeagleBone or the new BeagleBone Black? I'm using the original BeagleBone. it should work on the BeagleBone Black. Will you have any details available about what parts are needed to set it up? If your GPS receiver is using 3.3V logic, wiring it up is straightforward, similar to the Raspberry Pi NTP server. I will probably setup a page describing this. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
ntpd (poll=1) loopstats and ppstest using an eCAP clocksource and PPS root@beaglebone:~# ppstest /dev/pps0 trying PPS source /dev/pps0 found PPS source /dev/pps0 ok, found 1 source(s), now start fetching data... source 0 - assert 1371666297.5, sequence: 15602 - clear 0.0, sequence: 0 source 0 - assert 1371666298.3, sequence: 15603 - clear 0.0, sequence: 0 source 0 - assert 1371666299.8, sequence: 15604 - clear 0.0, sequence: 0 source 0 - assert 1371666300.00018, sequence: 15605 - clear 0.0, sequence: 0 source 0 - assert 1371666300.5, sequence: 15606 - clear 0.0, sequence: 0 To anyone interested, prepare a cross compiler (I'm using Linaro 2013.02) and try building a 3.8 kernel (https://github.com/beagleboard/kernel/tree/3.8). I will post the sources and patches. attachment: _offset.png___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On 6/19/2013 1:52 PM, Gabs Ricalde wrote: Are you using the original BeagleBone or the new BeagleBone Black? Will you have any details available about what parts are needed to set it up? Thanks! Chris Howard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
On Sat, Jun 15, 2013 at 12:50 PM, Doug Calvert dfc-l...@douglasfcalvert.net wrote: Can you explain what is different in this approach versus the traditional gps/pps without needing a custom clocksource? The default kernel uses TIMER2 for its clocksource, and is configured to use the internal clock derived from the on-board crystal. TIMER2 does not support event capture (hardware timestamps). The clocksource driver uses TIMER4 (which supports event capture) configured to use an external clock. On Sat, Jun 15, 2013 at 9:47 AM, Jim King j...@jimking.net wrote: I don't have a BeagleBone (yet), but I'm very interested in this. Are you going to post the driver somewhere when you're finished? Thanks, Jim I will post the sources and instructions when it's ready. On Sat, Jun 15, 2013 at 9:48 PM, Paul tic-...@bodosom.net wrote: On Fri Jun 14 20:13:51 EDT 2013, Gabs Ricalde wrote: As an alternative to the Net4501, the AM335x in the Beaglebone has timers ... I'm finishing the clocksource driver for Linux Which distribution and which kernel are you using? I am using the Angstrom-Cloud9-IDE-GNOME-eglibc-ipk-v2012.12-beaglebone-2013.05.28.img.xz image and rebuilt the kernel (3.8.13) from https://github.com/beagleboard/kernel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Beaglebone NTP server
Can you explain what is different in this approach versus the traditional gps/pps without needing a custom clocksource? On Fri, Jun 14, 2013 at 8:13 PM, Gabs Ricalde gsrica...@gmail.com wrote: As an alternative to the Net4501, the AM335x in the Beaglebone has timers that accept an external clock up to 25 MHz (TCLKIN) and can timestamp events on an input pin (TIMER4-TIMER7). Both sets of pins are available on the headers after an appropriate pinmux configuration. I'm finishing the clocksource driver for Linux, I'm testing it using the 10 MHz and PPS outputs of a LEA-6T. ntpd loopstats show +/- 0.1 us offsets, frequency is a flat 0.000 PPM as expected. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
