Re: [ntp:questions] shared memory driver not working under windows4.2.7p273++ build?
These simply indicate that as you noticed, the Windows port currently does not include the SHM driver. However, the ?code in refclock_shm.c once was portable to Windows, and probably can be made so again without too much effort. You'll need to edit ports\winnt\include\config.h to #define CLOCK_SHM to enable it, then fix any problems compiling the code under Windows. pkIndeed, we did get this up and running a couple of years back with a forked version ntp, but we then abandoned the fork in favour of your ongoing builds. If we sort this out and test it, would you consider merging it into your codebase? We really do not want to fork off permanently, especially with win8 in the offing. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Clock time synchronization of four computers
Nazim, If all you need is relative timing, pick a computer as master (a modern one one you rarely reboot is a good choice), edit the ntp.conf file to use a series (say 3) of external pool servers. then goto the other 3 machines, edit the ntp.conf file and point them at you master, NOT the pool servers. e.g. lets say you have 4 pc's PC1 192.168.1.1 (we will call this the master) PC1 192.168.1.2 PC1 192.168.1.3 PC1 192.168.1.4 PC1 (master on say 192.168.1.1) ntp.conf server 0.pool.ntp.org server 1.pool.ntp.org server 2.pool.ntp.org PC2 (192.168.1.2) ntp.conf server 192.168.1.1 minpoll 4 maxpoll 5 iburst prefer server 192.168.1.3 minpoll 4 maxpoll 5 iburst noselect server 192.168.1.4 minpoll 4 maxpoll 5 iburst noselect PC2 (192.168.1.3) ntp.conf server 192.168.1.1 minpoll 4 maxpoll 5 iburst prefer server 192.168.1.2 minpoll 4 maxpoll 5 iburst noselect server 192.168.1.4 minpoll 4 maxpoll 5 iburst noselect PC2 (192.168.1.4) ntp.conf server 192.168.1.1 minpoll 4 maxpoll 5 iburst prefer server 192.168.1.2 minpoll 4 maxpoll 5 iburst noselect server 192.168.1.3 minpoll 4 maxpoll 5 iburst noselect this will ensure they all synch up. the noselect will assist you with ntpq as you will see all the PC's in the same list and easily assess how well they align. -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of unruh Sent: Monday, 9 July 2012 12:25 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Clock time synchronization of four computers On 2012-07-08, Nazmul Islam nazmul.is...@gmail.com wrote: Hello, I have not used ntp processing before. I apologize in advance if my questions seem too novice. I am trying to synchronize the clocks of four computers. The timing does not have to be accurate but they have to be sync'd with each other. An error tolerance of 10-20 ms is acceptable. The computers are connected to the servers. Well a good way of synchronizing them is to have them all synchronized to UTC. Another is to synchronize one to UTC and the others to it as the server. I installed ntp by typing 'sudo apt-get install ntp' in the terminal. When I typed sudo ntpq -c lpeer, each computer was found to be connected to different timing websites. So what? They are all probably pool servers and synchronized to UTC. But if you want something else, edit /etc/ntp.conf and put in the same server lines. Therefore, I modified the ntp.conf server list and put the following ones for each of them (I am at NJ, USA): server nist1-ny.ustiming.org server nist1-nj.ustiming.org Why would you overload a level 1 server? server ntp.ubuntu.com However, each computer is still off. It's hard to find the exact time difference from eye-balling but I can see a clock time difference of roughly 1-2 second. No idea what that means, but on each of them use ntpq to look at the time offset from utc. You do not tell us what operating system you are using. ssh other.computer date;date will tell you if they are off by seconds. What should I do to synchronize these computers? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] losing time fast
pkmaybe you can post your ntp.conf file, so we can take a look. -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of E-Mail Sent to this address will be added to the BlackLists Sent: Thursday, 12 July 2012 3:42 AM To: questions@lists.ntp.org Subject: Re: [ntp:questions] losing time fast Anonymous wrote: I decided to try to synchronize to my other machines in my network rather than the ntp pool I was using and after restarting the PC with the problem it is fine. I do not know what the problem was since the other boxes are still using the ntp pool and not having any issues so I will revert this PC to its original config to use the ntp pool again and see if it recurs. You don't happen to have the Undisciplined Local Clock Driver 127.127.1.# configured? -- E-Mail Sent to this address blackl...@anitech-systems.com will be added to the BlackLists. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP on local networks
Hi Will, good questions. Before I offer an answer: 1. can you please provide samples of the ntp.conf files you have in place. It would really assist. 2. can you please provide the version of ntpd you are using? regards pk Questions: How can I configure a client/peer to always accept a server as good enough or atleast always accept the server when no other server can be contacted? (please answer for any platform below you can) Fedora 6: Fedora 10: Fedora 14: Ubuntu 11.04: Windows XP: How can I configure a server to always consider itself good enough and report that (lie if necessary) so that any badly configured client will still connect?(please answer for any platform below you can) Fedora 6: Fedora 10: Fedora 14: Ubuntu 11.04: Windows XP: Just for my own curiosity, why is just refusing to do what the operator wants the default behavior for clients/peers? Why not always synchronize as well as you can with whichever peers/hosts you can contact? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP on local networks
Exactly so. you can purchase a GPS receiver for well under $100 connect it to a serial port + pps on any of the pc's and have microsecond accuracy in a few hours. This 'master' can then serve time to all other PC's. The systems will then behave for years of unattended use. It is a far more cost effective solution. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of Charles Elliott Sent: Wednesday, 1 August 2012 8:26 AM To: 'Will Shackleford'; questions@lists.ntp.org Subject: Re: [ntp:questions] NTP on local networks Unruh had the correct advice: Buy a (cheap) GPS device for a master clock and propagate the correct time. If something is worth doing, it is worth doing right. Become a force, develop a reputation, for progress, one of the foundations of Western Civilization. The new BU-353, not the old one you can find for about $30, but the one that costs about $42, at USGlobalSat.com will do the job within a half second or better, and it is trivial to set up. All you need is a free USB port and a window, or preferably a thin roof, that faces the satellites. The Sure (search for Sure Electronics) GPS demo board is supposed to give much more accurate time, but it is a pain to set up. There are beaucoup people on this list that know a lot more about GPS clocks than I and most are willing to help, if you just ask. Meinberg at www.meinberg.de sells lots of very accurate clocks, and there are several other places like it. Search for GPS clocks or NTP clocks. Charles Elliott -Original Message- From: questions-bounces+elliott.ch=verizon@lists.ntp.org [mailto:questions-bounces+elliott.ch=verizon@lists.ntp.org] On Behalf Of Will Shackleford Sent: Monday, July 30, 2012 11:47 AM To: questions@lists.ntp.org Subject: [ntp:questions] NTP on local networks We have several computers with several different operating systems on a local network with no radios and no internet connection. The main goal is to keep them synchronized with each other. One frustration I have had is that clients tend to refuse to connect to servers on the network that are not good enough. I assume not good enough means too high a stratum although the error messages are not that clear. My current solution is to take a laptop to another room with an internet connection, let it sit for an hour and then bring it back to connect the local network where finally the other computers will accept it and synchronize with it. Questions: How can I configure a client/peer to always accept a server as good enough or atleast always accept the server when no other server can be contacted? (please answer for any platform below you can) Fedora 6: Fedora 10: Fedora 14: Ubuntu 11.04: Windows XP: How can I configure a server to always consider itself good enough and report that (lie if necessary) so that any badly configured client will still connect?(please answer for any platform below you can) Fedora 6: Fedora 10: Fedora 14: Ubuntu 11.04: Windows XP: Just for my own curiosity, why is just refusing to do what the operator wants the default behavior for clients/peers? Why not always synchronize as well as you can with whichever peers/hosts you can contact? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] is USB inherently evil, or only if something else is on the bus?
I suspect Dave is on the money here. I commonly see this with RS232 data from a multitude of GNSS receivers. GNSS hardware primary purpose is typically to compute position. We are leveraging off the very handy clock stability feature inherent of GNSS. It is not uncommon for firmware developers to develop code which takes the raw data (clocks, pseudo ranges and any augmentation data available), compute the position, then provide data on the output ports (USB / RS232 / Ethernet). This all sounds very good and reasonable. However, as satellite come and go, your receiver will systematically see a different constellation. This will trigger different computations in the firmware, which may execute faster or slower. Since data (typically NMEA) is output at the very end, the time that data is output is susceptible to the algorithms running beforehand. I can repeat this with ease on a variety of Trimble units. My thoughts would be: *Check the sky visiblity of your GNSS antenna. If you have poor visibility, chances are the computations are struggling, which is delaying the output of the ZDA. This would be my first thought. *Disable any augmentation (eg WAAS) to the device. That often causes different code execution paths. *Disable all NMEA strings other than ZDA *Lift the baud rate to 38400 or 57k. Do not use 115k. I have seen situations where the baud rate was too low for the data being shipped. Nasty. *Have a look at the ZDA string in a terminal program or the debug logs of NTPD. If you are lucky, the timestamps will *not* by integer seconds. They will be the actual timestamp the data was transmitted. If not, speak to your GNSS manufacturer. I have an old Trimble 4000 sitting here with RS232. The ZDA outputs integer seconds in the string. If I enable various options in the firmware, the data is as much as 700 milliseconds old by the time I get hold of it ;-( I think USB is a red herring here. PPS is clearly the best case, but if all you have is RS232 / USB then you need to be more careful. hope this helps. pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of Dave Hart Sent: Friday, 10 August 2012 6:16 AM To: Charles Elliott Cc: Rick Jones; questions@lists.ntp.org Subject: Re: [ntp:questions] is USB inherently evil, or only if something else is on the bus? On Thu, Aug 9, 2012 at 20:29 UTC, Charles Elliott wrote: The process shown in the graph repeats indefinitely using my BU-353W. In other words, the offsets always begin at about 300 ms, rise slowly to about 360 ms, vary erratically between 260 and 360 ms for about two hours, settle at 260 ms, and then rise slowly to 360 ms to repeat forever. It is not clear to me if the problem is the USB interface or the GPS device. Drift of that magnitude must be due to the GPS not USB-triggered latency. Moreover, the real problem is you're assuming the GPS is designed to provide the NMEA sentence(s) at a consistent delay relative to the top of the UTC second. Very often, they are not -- the timing of the NMEA sentences wanders by 100 msec or even more. To get better-than-WAN-NTP performance out of such a GPS, you need to be using its PPS signal. Essentially all USB-interfaced GPSes do not wire the PPS signal through to DCD or another suitable input handshaking line on their serial-to-USB chip. Thanks to Eric Raymond's bufferbloat-related efforts, there is hope we will see PPS exposed on more USB GPSes in the future, however. Cheers, Dave Hart ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP and VMware
Hi Ali, when you state ' do not synchronize their times with the server', what do you mean? if you run 'ntpq -p' on the client side, you should see something like this remote refid st t when poll reach delay offset jitter == SHM(3) .XPPS. 0 l-800.0000.000 0.000 SHM(2) .XZDA. 0 l-800.0000.000 0.000 +172.23.21.221 .PPSE. 1 u78 3770.2601.631 0.532 *172.23.21.9 .GPS.1 u88 3770.4431.386 0.448 172.23.21.244 .STEP. 16 u 4d800.0000.000 0.000 TD-GITCENTRAL 172.23.21.9 2 u48 3770.1630.196 1.284 172.23.21.243 .PPSI. 1 u78 3770.1981.976 0.864 The important part here (for now) is the reach to the server. if 377, you have a good connection between the client and the server. Once connection is proven, we can deal with the clock selection process. regards -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of Ali Nikzad Sent: Tuesday, 14 August 2012 12:35 PM To: questions@lists.ntp.org Subject: [ntp:questions] NTP and VMware Hi, I have a cluster which its computers are not connected to Internet. One Linux based and five ESXi based servers which host virtual machines in a vSphere cluster. I need time synchronization between the hosts. Since ESXi supports NTP, I configured the Linux based node to serve as the NTP server and the ESXi nodes as NTP clients. I configured the server's ntp.conf as follows: #192.168.2.10 driftfile /etc/ntp.drift server 127.127.1.0 fudge 127.127.1.0 stratum 10 tos cohort 1 orphan 11 restrict source nomodify restrict 192.168.2.0 mask 255.255.255.0 nomodify notrap and the clients' ntp.conf file: #192.168.2.X driftfile /etc/ntp.drift server 192.168.2.10 tos cohort 1 orphan 11 restrict source nomodify restrict default kod nomodify notrap nopeer restrict 127.0.0.1 The problem is clients do not synchronize their times with the server. What can be the cause of the problem? Thank you, Ali ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Visual clock display?
Hi Ralph, NTP is designed to synch your PC clock to UTC. If it is doing its job correctly, your PC clock time == utc time, so any software displaying time will do the trick. If you would like to get hold of NTP's best estimate of time, I would recommend the ntpq qc tool. ntpq -c rv which returns associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync, version=ntpd 4.2.6p5@1.2349-o Jul 06 19:25:05.01 (UTC+08:00) 2012 (3), processor=x86, system=Windows, leap=00, stratum=2, precision=-10, rootdelay=0.140, rootdisp=8.054, refid=172.23.21.9, reftime=d3e55814.b925fac3 Mon, Aug 27 2012 10:21:08.723, clock=d3e55836.1ba456d8 Mon, Aug 27 2012 10:21:42.107, peer=54235, tc=3, mintc=3, offset=-2.315, frequency=0.612, sys_jitter=1.090, clk_jitter=1.770, clk_wander=0.250 Just parse the output from ntpq and you have what you seek. The entry 'clock=' is the one you are after, so my current time is Mon, Aug 27 2012 10:21:42.107. However, there is not a clock on the planet that is perfectly correct (as far as I know), so if you want to be pedantic, you should also parse out the 'offset=xxx' and report this as the estimate of accuracy (in millisecs). hope this helps. -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of Ralph Aichinger Sent: Sunday, 26 August 2012 3:08 AM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Visual clock display? Chris Albertson albertson.ch...@gmail.com wrote: The limit of accuracy of the visual clock is the refresh rate of the monitor. One the old CRT monitors there was a vertical sync that ran at about 60 to 100 Hz. I think LCDs have something like this too. You can do better than 100 mSec using your method. In fact it can approach the vertical sync limit. 100ms is just fine for me, I think. I don't know how much the console driver or a GUI layer adds. The system can do better timing but the 100 Hz (or so) screen refresh is the limit. Actully you eyes can't see a change that is faster than about maybe about 30 mSec. But you CAN see 100 mSec ticks. Run your update loop at 100Hz and you will be fine Is there an official program that displays the time of the ntpd process? Or is one supposed to get time for uses like this from the system clock? Not that I think it makes a difference with 100ms accuracy, but as a matter of principle it would interest me. /ralph ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP time compare util
Ivan, That tool would be ntpd. Just add all the servers you want to monitor, restart ntp and then run ntpq -p to see them all lined up. You can log the data to peerstats files to a file and make long term plots. Regards - Original Message - From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org questions-bounces+p.kennedy=fugro.com...@lists.ntp.org To: questions@lists.ntp.org questions@lists.ntp.org Sent: Tue Aug 28 18:45:00 2012 Subject: Re: [ntp:questions] NTP time compare util telsar no...@nowhere.com writes: On 8/24/2012 7:52 AM, Harry Bloomfield wrote: [Cross-posting to news:comp.protocols.time.ntp, for obvious reasons.] Out of nothing more that idle curiosity, I am looking a utility which can display the time from several internet time servers at once. I also need to be able to set which time servers it interrogates. Anyone come across such a utility please? ntpdate comes to mind, but it could just be a Unix phenomena. If you search on Network Time Protocol (NTP) you will see much. ntpdate is a suite of client/server programs to do all this stuff. [...] The ntpdate [1] version I use seems to come from the ntp.org package [2], apparently developed by the developers of the NTP protocol itself. Ordinarily, ntpdate(8) is used to set the system's clock to the time obtained by (AIUI) averaging (with weights) the times reported by the servers specified. However, when started as follows, it can show the difference without setting time: $ /usr/sbin/ntpdate -uvq 0.debian.pool.ntp.org 1.debian.pool.ntp.org ... And if the debugging mode is also set (with -d), it shows the individual times reported, too. [1] http://en.wikipedia.org/wiki/Ntpdate [2] http://ntp.org/downloads.html -- FSF associate member #7257 http://sf-day.org/ ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Have Pi, have GPS = low powered NTP server?
Hi Dave, good feedback. I have had the pi running for several days now without a hitch. Due to my dynamic IP (pending a static ip), you can find the pi and associated ntp server at: http://secondthoughts.no-ip.org I made a small realtime time-series plot and a page displaying ntpq info so I can more easily review performance. I fully intend to use serial GPS+PPS when it arrives (slow boat from china), but will continue to build the web site for monitoring the service in the meantime. I am currently building the web page to add additional ref clocks. I do se occasional spikes in the offset. you can see them in the timer series plots which are based on loopstats files. I would hope they disappear when I have pps. I am not sure if this is pi/ethernet or the refclock (which is not close-by). My final use-case is on our internal LAN's at work where we have a GPS unit always on hand, but this is a homework project right now, so the going is a bit slow. I have not seen any lockups yet, and will try to keep it running as long as possible without a reboot. If you have seen it, I am sure it will pop up for me as well. If we get them, the pi is a showstopper for me. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of DaveB Sent: Wednesday, 29 August 2012 4:32 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Have Pi, have GPS = low powered NTP server? In article b0590fa0-d352-4ce0-8504-770846090...@googlegroups.com, pktr...@gmail.com says... Hi, I have my pi running on the web right now at http://121.221.94.250/ I made a small web site to expose various parameters in realtime. Still waiting for my gps unit, but I am pretty happy with millisecond from live internet sources. PPS is next. The website needs a little more polish, but the basics are there. http://121.221.94.250/ Unreachable, 08:19 UTC Wednesday 29th August. I've seen on another site, that people using the chipset based serial port with GPS and other devices, and have *Much* better results than when using a USB hosted serial port. There are still issues with the Pi's network port, as that aparrently is a USB driven device on board, resulting in more latency than might be expected otherwise, and some extra variability too. I also found that the Pi would lock up and need a power cycle, if left running the default NTPD service for anything more than two or three days. It was predictable and repeatable, but I've not tried updating the OS (or NTP) and doing that again. That was using the original Debian distro for the thing. At this exact time, it's back in it's box while I make room for it by doing other things, much more important according to domestic management. I have other plans for it. Regards. Dave B. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP time compare util
I had a think about this oddball question last night, and decided to explore it a little further. Assuming I understand the original question from Harry Bloomfield, it came to me that the we already have the data Harry is looking for in the peerstats files, ie we have a data record for each response from each configured server... 1.pool.ntp.org Time, offset, jitter, delay Time, offset, jitter, delay Time, offset, jitter, delay an.other.server Time, offset, jitter, delay Time, offset, jitter, delay Time, offset, jitter, delay Harry was looking for a display of this, so I spent a couple of hours and made something which displays the live data... http://secondthoughts.no-ip.org/page-peerstats.php You will see from the plots, I am still fooling round with the conf file, but general principle is to make a utility which can display a 24hour data 'time quality' from several servers at once (Harry asked for the 'time' from several servers, but I interpret that to mean the quality of the time from those servers, as all the humans I know cannot deal with milliseconds) Maybe Harry is really after super-humans (ie the borg), so they are all in collective sync, but this is as good as I can do right now. regards ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] PPS and NMEA
Prab, this is a very ambiguous question, so I shall answer it as briefly as the question demands. PPS requires specific hardware and wiring. No PPS does not. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of ksprabha Sent: Monday, 10 September 2012 7:48 AM To: questions@lists.ntp.org Subject: [ntp:questions] PPS and NMEA Hi, Kindly let me know what is the difference between NTP with PPS and NTP with out PPS. Thanks Prab ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP client configuration
Ben, you have not yet stated what OS you are using. I think we need to know the flavour of windows you are using. If I read the mail thread, I see you have the following issues... 1. You have a problem with startup being too slow to achieve acceptable synchronisation. 2. Your windows boxes sometimes drift off a long way compared to the server. 3. You are now looking to patch up a poorly designed framework with software hacks to step the clocks back into alignment rather than fix the root cause of your troubles. My advice would be as follows... A. Decide what your startup AND synch criteria are (and let us know). If it cannot be met, you are wasting your time with NTP, and need to look elsewhere. B. Forget using localhost as a time source. More trouble than it is worth. C. Get a stable time source for your server. If you have internet, use it. If not, get a GPS based server and use it. As a rough guide, A Windows server will give you milliseconds quality reference clock. A Linux box will give you a Microseconds quality reference clock. D. Sort out your client PC's install of NTP. They are clearly not well installed or configured at this time. E. Monitor your client PC's (and indeed the server PC) over both the long term (days) and short term (minutes) to confirm both the startup time from boot and the stability are acceptable under regular use. Apologies if this is a little prescriptive and blunt (in my defence, I am a Yorkshireman), but we are a windows shop and have great success with ntp. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of unruh Sent: Friday, 28 September 2012 5:20 AM To: questions@lists.ntp.org Subject: Re: [ntp:questions] NTP client configuration On 2012-09-27, Benjamin CABUT benjamin.ca...@rsacosmos.com wrote: Hello, I don't car in my application to have the correct UTC time. What I care is that all my computers share exactly the same time. Our application is not connected to internet. So only time I can use as a reference is local clock of one computer. OK, look up orphan mode. But again why are you suing a windows machine as your reference? Windows is not known for its timekeeping ability. Use for example one of your Linux machines instead. I can realy tell you that my client is not sync some times! it happen in 2 ways: - when I start my computers, it need arround 5 minutes to be sync, it is a problem for me ntpd is NOT designed for rapid convergence. 5 min is very fast as far as ntpd is concerned. - when one computer has heavy operation to do, then ntp client desync What do you mean when one computer? The server? a client? And what is a heavy operation? and I have offset that can be 2 seconds, and stay like this during sereval minutes. You have other problems. ntpd is NOT designed to correct clocks which jump around by seconds. You need to get your clocks to behave themselves first so that their time does not jump around. so It realy need a long time to ntp client to detect the big desync. I do not want to rewrite ntp. ntpq gives the offset between clock of client and clock of server. As you say the best way for me is that ntp is working perfectly, but it is not the case. Your idea and Mill's idea of working perfectly is different. He designed it so that it will correct clocks which run stably (loess than say 100PPM rate error always). It is NOT designed to hadle clocks whose rates can vary by more than that, or whose time can jump around. chrony (sorry does not run on Windows) does a bit better but again it would have trouble with your clocks as well. I don't know how to improve this by configuration. Depends on what you mean by improved. So I was just wondering if I could get the offset in my software to solve my problem... I think you need to figure out what your problem is first. Regards. Le 27/09/2012 20:39, unruh a ?crit : On 2012-09-27, Benjamin CABUT benjamin.ca...@rsacosmos.com wrote: Hello, We are using Meindberg NTP client and server. Our configuration is: - 1 Computer under windows that is server server 127.127.1.0 Why would you be using a windows machine as your server. Windows is not a great platform for time. And why in the worl would you have it be using the local refclock. That should never be used. Where in the world is that computer getting its time from? broadcast 192.168.2.255 minpoll 4 maxpoll 4 iburst disable auth - several computer under linux + computers under windows, client of this server: server 192.168.2.250 minpoll 4 maxpoll 4 iburst broadcastclient disable auth My problem is the following: Mainly on windows computer, sometime, depending what the computer is doing, there is a big offset between clients and server. (Big for me is more than 500ms). I would like to know if it is possible to setup client so as soon as he
Re: [ntp:questions] Using ntpd with custom clock
Forgive me if I am wrong, but this is a very odd request. As far as I can tell, the request is for the NTP corrections to the system clock to be used to correct a different clock. I cannot quite understand how this is of practical use. It is like diagnosing the faults on your car engine and then applying the corrections to a train engine. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of Rob Sent: Wednesday, 17 October 2012 3:06 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Using ntpd with custom clock Chuck Swiger cswi...@mac.com wrote: Hi-- On Oct 16, 2012, at 2:49 PM, Felipe Blauth wrote: 2012/10/16 Brian Utterback brian.utterb...@oracle.com I think the original poster is asking to do something a little bit different than the usual. If I am reading it right, he is not asking how to get ntpd to read a custom clock as a source of time (which as noted is what a refclock is for). I think he is asking how to get ntpd to *set* a custom clock, treating it as it would the system clock, so as to sync the custom clock with the upstream NTP server time. That's exactly what I want to do. OK. You can either hook into ntpd's calls to get/settimeofday() and adjtime() as you initially suggested, or perhaps look into the SHM driver. The latter is a generic interface that puts clock timestamps into shared memory; but you can read from SHM instead of writing, if you like-- would be easier if you have something like a GPS receiver and gpsd populating the SHM timestamps. Funny that, after you initially seem to indicate that you have understood the question, you still come up with the SHM driver that is a REFERENCE CLOCK driver, not an ADJUSTMENT CLOCK driver. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Using ntpd with custom clock
Hi, Apologies if I upset you. I responded as I wish to provide assistance, but either I do not really understand the question or the question is rather too vague (for me at least). A little more detail may well generate rich returns from some pretty experienced folks (for free). I believe that is called a conversation. Quite popular in the old days. In my experience, keeping the conversation friendly usually gets a better outcome. regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of unruh Sent: Wednesday, 17 October 2012 5:34 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Using ntpd with custom clock On 2012-10-17, Rob nom...@example.com wrote: Kennedy, Paul p.kenn...@fugro.com.au wrote: Forgive me if I am wrong, but this is a very odd request. As far as I can tell, the request is for the NTP corrections to the system clock to be used to correct a different clock. I cannot quite understand how this is of practical use. It is like diagnosing the faults on your car engine and then applying the corrections to a train engine. When it is an odd request in your opinion, it does not mean it is not valid. It may explain why there is no standard code in ntpd to handle this situation, but it is no excuse to give wrong answers or boilerplate answers. It happens so often on this group. There are two questions that very frequently pop up: - I want to test and validate how ntpd handles an unusual situation (like a fault or a leap-second) - I want to keep an island of sytems synchronized to the same time (but I don't care how that time relates to UTC) All the time we see those responses that declare the question as odd, or try to modify the requirements of the poster, or add a new piece of hardware (like a GPS receiver). And usually the responses are from the same small group of posters. It is really lame. When you cannot answer the question, you can always keep quiet. There is no need to always jump on the soapbox. And since you did NOT give an answer to the poster, why did you not keep quiet? As far as I know ntpd does not handle the sitution that the poster apparently wants to handle. He will need to write code to use something ( the system clock, the output from a gps, the data from an ntp server) to discipline his external hardware clock. If the clock allows its rate to be changed, this should not be too hard. If it does not, it will be more difficult. But we have no idea what the OP really wants. He has been very very skimpy in telling us. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP tunning for OWD measurements
Pedro, Unruh makes some good points here. Here is a good start point ntp.conf to get the stats logged at each server... #@Pedro, this section will log some ASCII stats of the clock quality. # You can easily plot them in scipy or your tool of choice. This is your 'baseline' for quality assurance. # /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help driftfile /var/lib/ntp/ntp.drift # Enable this if you want statistics to be logged. statsdir /var/log/ntpstats/ statistics loopstats peerstats sysstats filegen loopstats type day link enable filegen peerstats type day link enable filegen sysstats type day link enable #@Pedro, chance this to your servers S1, S2. As you are on a known network, and conducting controlled experiments, I would strongly advise you to NOT use internet (pool) NTP servers. #@Pedro, make a decision on the prefererred server and make it so server S1 iburst minpoll 3 maxpoll 4 prefer #@Pedro, set the other servers to 'noselect', which means you will gather the stats, but the various test sites will never flip to them, which would screw up your tests. server S2 iburst minpoll 3 maxpoll 4 noselect PkBy controlling which refclocks the various test sites use, you should see they synch up well enough. We do this regularly. Unruh makes a very good point on the delay Vs Offset. You should certainly be doing this as it will reveal your QoS. PkI would also make time series plots of Time Vs Offset with all the test sites in the same plot. This will give you an idea of synchronisation over your measurement period. They are very easy to make in python / excel. PkUnruh also make a good point on the use of GPS, but if it is not available, then you need to sit (and recognise you are sitting) in the 2nd class seats. It will be important to identify and understand the signal from the noise. If your clock offset are out by milliseconds, then you can only hope to measure 1 way delay better than milliseconds, but if they are good to microsecond, then you might get meaningful results. PkGood luck, and I hope this helps. Regards Pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of unruh Sent: Saturday, 27 October 2012 8:42 AM To: questions@lists.ntp.org Subject: Re: [ntp:questions] NTP tunning for OWD measurements On 2012-10-26, pret3n...@gmail.com pret3n...@gmail.com wrote: An NREN is a National Research and Education Network. We are talking about 26 servers spread all over the country and in the islands, so your figures are a bit off, I'm afraid. $50 don't cover the expenses associated with getting a GPS for every single server, and like I said before, it's simply undoable. And I'm just a student, I don't get any payment for this, instead I pay my tuition - as I should. But this is getting out of subject :-) Agreed. It is your supervisor that should pay for that. I suspect that you will discover that there is a huge (millisecond level) jitter in the network. As was suggested, your first thing to do, before doing anything else, should be to get ntpd running on all the machines ( you probably already have it) making sure that the measurements log is active statistics peerstats in /etc/ntp.conf with the servers being those level 1 servers you mentioned. Then after a few days of running, plot the offset against the delay, and look at that graph. You may well notice wings on that graph with slope of 1/2 . Those are asymmetric delays. The spread of the central blob will also give you an idea of the noise on your connection. Now with that information, you can begin to make plans and to know what kind of errors to expect, and to compare them with the requirements. Then, get your supervisor to put out for a a few gps receivers, wire them up so that they can simply be plugged in, and send them to the IT guys at the a few of the sites. Set up ntp to use pps on those sites, and now you can accurately determine the one way delays between those sites. You can now get an estimate of the assymetry of the connections, and compare that the overall network noise. Anyway, thanks for your remarks and suggestions. Pedro On Saturday, October 27, 2012 12:31:28 AM UTC+1, unruh wrote: On 2012-10-26, pret3n...@gmail.com pret3n...@gmail.com wrote: Hi all, and thank you for your answers. I'm afraid I might not have been clear about my objectives, so I'll try to explain clearer. I'll also try and keep the lines smaller, and please, excuse me if I make any mistakes, as english is not my native language. This project involves a NREN, which interconnects several institutions. Whatever and NREN is. The current architecture is as follows: two main servers (let's call it S1 and S2) placed in the NREN infrastructure at two different places in the country, and several servers (X1, X2, Xi) placed at the edge
Re: [ntp:questions] Using Trimble TSIP under Linux
Dave, ntpd will be in /usr/bin or /usr/sbin. On my pi the /usr/sbin is the one in use. Just copy across your newly built binary and restart with a sudo /etc/init.d/ntp restart you can always kill the ntpd process (with a sudo ps -e | grep ntpd followed by sudo kill -9 processname), then run the one you bult interactively to make sure all is well. The debug offerings are really handy in the interactive mode. pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of David Taylor Sent: Monday, 29 October 2012 5:11 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Using Trimble TSIP under Linux On 29/10/2012 08:38, Rob wrote: David Taylor david-tay...@blueyonder.co.uk.invalid wrote: - use sudo ppstest /dev/pps0 and see assert pulses coming in (the clear field is always 0 though, perhaps the 150 microsecond pulse is too narrow?) That is a problem! Now I remember... I tried different GPS receivers when writing the code for the PPS support in gpsd, and there was a receiver for which it would not work because the pulse is too narrow for the technique used in gpsd. It was the Trimble, I remember now. You need to add a circuit to stretch the narrow pulse into a 100ms pulse. The exact duration is not important. Just arrange for a monostable multivibrator that gets triggered by the rising edge of the pulse and extends the pulse by R/C time. Make sure the pulse is shorter than 500ms or the autodetection logic will focus on the wrong edge of the pulse. Thanks, Rob. For the moment I have decided to use the pps-gpio code which has been written for the Raspberry Pi, rather than the gpsd route. This is producing valid data when running the ppstest (although the entries of 0 in the clear values worry me slightly), and from the NTP log I believe that the version I have may not have ATOM support. I've recompiled NTP, and am thinking about installing it I really would prefer not to have to add extra hardware at this point. -- Cheers, David Web: http://www.satsignal.eu ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Using Trimble TSIP under Linux
Hi
I did not encounter this, but I would try the following...
ps -e | grep ntpd
To see if ntp is accidentally running already
sudo chmod 777 /usr/sbin/ntpd
To make sure the root user (that's the one who runs 'services' has permission
to run ntpd.
My guess is the latter.
If you get more grief from the atom driver, maybe try the NMEA RMC. Works a
treat for me.
Good luck
Pk
- Original Message -
From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org
questions-bounces+p.kennedy=fugro.com...@lists.ntp.org
To: questions@lists.ntp.org questions@lists.ntp.org
Sent: Mon Oct 29 18:45:21 2012
Subject: Re: [ntp:questions] Using Trimble TSIP under Linux
On 29/10/2012 09:44, Kennedy, Paul wrote:
Dave,
ntpd will be in /usr/bin or /usr/sbin. On my pi the /usr/sbin is the
one in use. Just copy across your newly built binary and restart with a
sudo /etc/init.d/ntp restart
you can always kill the ntpd process (with a sudo ps -e | grep ntpd
followed by sudo kill -9 processname), then run the one you bult
interactively to make sure all is well. The debug offerings are really
handy in the interactive mode.
pk
Making progress, Paul, thanks! I managed to get gpsd to autostart with
the dpkg-reconfigure, but on ntp it said: ntp is broken or not fully
install. I still says that after I copied the ntp executables from my
local directory to /usr/bin. On trying to restart ntp it failed:
pi@raspberrypi ~ $ sudo /etc/init.d/ntp restart
[ ok ] Stopping NTP server: ntpd.
[] Starting NTP server: ntpd/usr/sbin/ntpd: The ``user'' option has
been disabled -- built without --enable-clockctl or --enable-linuxcaps
ntpd - NTP daemon program - Ver. 4.2.7p314
USAGE: ntpd [ -flag [val] | --name[{=| }val] ]... \
[ server1 ... serverN ]
failed!
but trying to run ntpd from the command-line it works correctly:
pi@raspberrypi ~ $ sudo /usr/local/bin/ntpd
pi@raspberrypi ~ $
and continues to run after I log out, with excellent PPS support. I
took all the defaults when building NTP and set no special options
myself. What have I done wrong now!?
--
Cheers,
David
Web: http://www.satsignal.eu
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Re: [ntp:questions] What is the NTP recovery time from 16s step in GPSserver?
Dave, I believe the answer to your question is 12.5 minutes. This is the time it takes to receive the full set of 25 almanac frames, which contains the GPSTime/UTC offset (amongst other things). http://en.wikipedia.org/wiki/GPS_signals#Almanac regards pk ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] What is the NTP recovery time from 16s step inGPSserver?
That is one description. Another would be it is a fully functional linux computer with LAN, HDMI, SVideo, Audio, USB, Serial, and a GPIO bus with the footprint of a credit card, no moving parts which draws only 2-3 watts for US$35. My pi units run various processes such as NTP, web hosting and data IO at a fraction of the cost of conventional hardware. Step changes in computing technology are pretty rare. Having developed on them a couple of months, I put the pi into that category. Oh yes, and the silence of the pi's is worth the US$35 alone. It really depends if you prefer your glass to be half full or half empty ;-) regards pk -Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of David Woolley Sent: Friday, 2 November 2012 12:32 AM To: questions@lists.ntp.org Subject: Re: [ntp:questions] What is the NTP recovery time from 16s step inGPSserver? unruh wrote: Interrupt latencies in my measurements tended to be at the one or 2 microsecond level. (drive a pin on the parallel port up, measuring when The Raspberry Pi is basically a headless PDA, using smart phone type processors. It is optimised for power consumption, not speed. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Using PPS
-Original Message- From: questions-bounces+p.kennedy=fugro.com...@lists.ntp.org [mailto:questions-bounces+p.kennedy=fugro.com...@lists.ntp.org] On Behalf Of David Taylor Sent: Friday, 28 December 2012 2:33 PM To: questions@lists.ntp.org Subject: Re: [ntp:questions] Using PPS On 28/12/2012 00:15, Joshua Small wrote: Hi David, Thank you for this. I guess this leads me to the question of how do I debug this, since I seem to have neither of those features listed. I do note that your example uses the ATOM driver 22, whereas several pages have referred me to using the driver 20 as a better option - was this a bad move? I did have to compile my own kernel as I added other modules not present in the precompiled kernels featuring the PPS pi@raspberrypi ~ $ ntpq -p remote refid st t when poll reach delay offset jitter == *GPS_NMEA(0) .GPS.0 l4810.000 -27.038 0.004 +wombat.osoal.or .GPS.1 u1 641 43.639 144.936 1.213 warrane.connect 130.95.179.802 u1 6415.842 144.114 0.574 +203.192.179.98 223.252.32.9 2 u2 641 21.483 103.720 1.765 pi@raspberrypi ~ $ ntpq -c rv associd=0 status=0415 leap_none, sync_uhf_radio, 1 event, clock_sync, version=ntpd 4.2.7p334@1.2483-o Mon Dec 17 22:19:03 UTC 2012 (1), processor=armv6l, system=Linux/3.2.27+, leap=00, stratum=1, precision=-18, rootdelay=0.000, rootdisp=1028.296, refid=GPS, reftime=d4875ebc.1c973e69 Fri, Dec 28 2012 10:56:44.111, clock=d4875ebd.51aa5e49 Fri, Dec 28 2012 10:56:45.319, peer=1115, tc=3, mintc=3, offset=-36.735257, frequency=-14.904, sys_jitter=47.867458, clk_jitter=58.208, clk_wander=0.000 (the somewhat large offset is due to the fact I only turned this on two seconds before running the command.. they do level out) I'm running dev version 4.2.7p334, I also tried stable 4.2.6p5 with no difference. Joshua, The fact that you don't have the o as the tally code (ntpq -p) and the lack of kern (ntpq -c rv) says that PPS isn't working. My understanding (and I am open to correction) is this: - the type 20 driver can detect PPS transitions on the DCD RS-232 line, and can timestamp those. - the type 22 driver relies on the OS detecting the PPS transition time, via PPS built into the kernel of the OS. - in the Raspberry Pi, there is no DCD line, and hence no DCD timestamp, and hence the type 20 driver will not detect the PPS transitions. - in the Raspberry Pi, there is direct I/O supported for some of the GPIO pins, and one extension to the basic OS has been to use one of those pins for PPS support. This requires both a different kernel, and a module driver add-on. That's why I used the type 22 driver rather then type 20. -- Cheers, David Web: http://www.satsignal.eu ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions I use the type 20 driver on my pi, and PPS to the GPIO boards works a treat with an $RMC or $ZDA string. regards pk ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Using PPS
Yep. My bad. Definitely the GPIO port. Pk On 28/12/2012, at 5:45 PM, David Taylor david-tay...@blueyonder.co.uk.invalid wrote: On 28/12/2012 06:53, Kennedy, Paul wrote: [] I use the type 20 driver on my pi, and PPS to the GPIO boards works a treat with an $RMC or $ZDA string. regards pk That's helpful to know, Paul. Do you mean ports rather than boards, or are you using an add-on board? What modifications did you make to the kernel to get the PPS detected? -- Cheers, David Web: http://www.satsignal.eu ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] PPS woes
I split the gps+pps (20) into gps and pps (20 22) and that solved the problem. I do wish I knew what happened. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] How to determin hardware latency for PPS offset given simple tools.
I have four GPS receivers into four different computers. I've assumed that I should be able to get small offsets between them but to do so I need to set time1. If that's the correct approach how do I pick the right system to be the benchmark. So far I've just been assuming that the purpose built M. Tharp server should have the lowest latency but I'm not sure -- in any case, at present, I can't adjust it. Each machine in the truncated table below (except 210) has a time1 value derived in an ad hoc fashion. l rrefid st delay offset jitter == 1 o22.0 .PPS.0 0.000 -0.001 0.001 2 +244 .PPS.1 0.0680.000 0.006 2 *210 .GPS.1 0.514 -0.008 0.136 2 +192 .PPS.1 0.4550.008 0.032 I feel as if this topic should be clearly explained somewhere but I've been unable to find it. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] How to determin hardware latency for PPS offset given simple tools.
On Saturday, May 25, 2013 1:06:48 AM UTC-4, unruh wrote: GPS receivers are not particularly good time sources UNLESS you use PPS. All of my clocks use PPS and in fact none of them use GPS to number the seconds except the one that uses refid GPS. That clock is a purpose built NTP-equivalent server called a Laureline which uses PPS and numbers seconds via serial input. Per the refclock document the PPS/NMEA (20/22) drivers use time1 to correct for PPS offset while 22 uses time2 to correct for serial latency. Since the clocks differ by O(100 microsec) without time1 correction I assumed that was internal rather than network latency. If you use PPS they should all agree to the 1micro second level. They do per ntpq given resp. 124, 151 and 85 microsecond time1. grabbing times via the net from the those computers will be dominated by network issues. I've been assuming that since I get fairly consistent offsets (fudged or not) and jitter that network latency is not the culprit. But I'm clearly confused about something. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] How to determin hardware latency for PPS offset given simple tools.
On Saturday, May 25, 2013 3:05:13 AM UTC-4, David Taylor wrote: What happens with the fudge set to zero? Please show the table for each machine. Showing 192.168.0.2 and .244 with time1 = 0 as compared to the first post where time1 was ~100 microsec. These two have gigabit interfaces. 0.2 is driven by a Garmin 18x and 0.244 is driven by a Firefly (I). 0.2 remote refid st t when poll reach delay offset jitter == o127.127.22.0.PPS.0 l18 3770.000 -0.001 0.002 +192.168.0.244 .PPS.1 u-8 3770.075 -0.128 0.001 *192.168.0.210 .GPS.1 u78 3770.5190.117 0.098 0.244 remote refid st t when poll reach delay offset jitter == o127.127.22.0.PPS.0 l58 3770.0000.000 0.002 +192.168.0.2 .PPS.1 u48 3770.0790.132 0.003 +192.168.0.210 .GPS.1 u48 3770.5470.253 0.135 *192.168.0.192 .PPS.1 u38 3770.4750.262 0.036 ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] How to determin hardware latency for PPS offset given simple tools.
On Sunday, May 26, 2013 5:25:28 PM UTC-4, unruh wrote: Lan will have delays of the order of .15ms (worse for gigabit) This not the delay reported by ntpq. Is it wrong or are you talking about another measurement? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] How to determin hardware latency for PPS offset given simple tools.
On Thursday, June 20, 2013 5:51:50 PM UTC-4, E-Mail Sent to this address will
be added to the BlackLists wrote:
enable stats [etc. etc.]
As noted earlier I've done that or it's not applicable. E.g. I only use the
PPS driver and my seconds are numbered by an appliance that doesn't run ntpd.
On one system at a time, ...
have several other NTP servers configured {I usually shoot for 6 to 10}
I don't have six to ten stratum one servers (but maybe I should) and it doesn't
seem useful to compare my 500 microsecond offsets to non-local clocks.
with all involved systems continuously running for more than one day;
take an average ...
In another thread (and some here) I explain how I've done that and I don't
really like the e.g. 124 microsecond time1 I derived. However it does result
in O(1) microsec. offsets between some of my clocks.
perhaps the PPS signal is inverted?
It's not.
It seemed like David Taylor covered that on may 25th.
Yes. While I appreciate the suggestions and the good will behind them they
don't seem informed by my question/problem description.
My key point is that ntpq appears to be telling me odd things. E.g. my network
is low latency, symmetric and consistent but some of my offsets are one or two
orders of magnitude beyond other offsets.
So my question is how to find what I hope is hardware latency using the tools
at hand or the coverse given multiple S1 clocks with O(10) microsecond offsets
which one is right.
I expect I will move a set of them to a 10/100 switch and see if that makes a
difference.
Ideally all my clocks pairs would look like this (both have time1 0):
localhost oPPS(0) .PPS. ... 3770.0000.001 0.001
black +aster .PPS. ... 3770.065 -0.003 0.004
localhost oPPS(0) .PPS. ... 3770.0000.000 0.004
aster +black .PPS. ... 3770.0660.007 0.010
But maybe some of them are just not up to the task:
aster *ntp1 .PPS. ... 3770.5260.129 0.166
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Re: [ntp:questions] How to determine hardware latency for PPS offset given simple tools.
On Friday, June 21, 2013 9:16:28 PM UTC-4, Charles Elliott wrote: You may be making a mistake using stratum 1 servers All the S1 servers are on my local network. I (temporarily) have six. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Roof antenna, which one, would you bother?
On Friday, January 3, 2014 5:54:45 AM UTC-5, Ralph Aichinger wrote: Or would you not bother at all, and just put some puck into the window (which probably works too)? I'd put a timing antenna in the attic (used Symmetricom 58532A/VIC100s, which I have, are cheap). I have one near the ceiling on the upper floor and it's fine for a modern (SMT) GPS but only acceptable for older (T-bolt) units. I also have mag puck in south facing window. The 58532A is much better. Finish up with a GPS with some internal visibility (e.g. SMT), a Symmetricom/Agilent/HP splitter and Bob's your uncle. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Quality vs. Quantity
(I inadvertently sent this only to Terje Mathisen) On Sun, Mar 23, 2014 at 12:07 AM, Danny Mayer wrote: What do you mean by load-balancing? NTP cannot be load-balanced. Of course it can (at some cost). On Sun, Mar 23, 2014 at 3:43 AM, Terje Mathisen wrote: You really do NOT want load-balancing of ntp servers!!! Ideally the server would manage this but address based load balancing (presumably as practiced by USNO) solves some problems. DNS balancing (viz. time.nist.gov or pool.ntp.org) is pretty weak but some of that can be mitigated in the server. Still I'd rather have three IP addresses fronting 300 servers than three IP addresses fronting three servers assuming the goal is resilient remote service. But I might still question the assumptions of the OP (the question is unclear) since I expect the number of queries to central public infrastructure to decline over time as the number of clients decrease. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] dynamic stratum changes
Hi, I'm setting up ntp on an isolated net. Some of our linux machines run a custom time protocol that synchronizes the kernel to GPS time to sub millisecond accuracy. I've got my ntpd.conf using the local oscillator (127.127.1.1) clock at stratum 1. I'm looking to see what I should do when my custom time protocol has an error and can't synchronize time anymore. I would like to degrade my stratum so that other machines will choose a better source of time, depending on how bad my custom protocol fails. I'd rather not kill and restart ntpd, as that just puts load on the machine for no good reason, and seems very inelegant. I looked into ntpdc "fudge" command, but it doesn't support the stratum option. Is there some elegant way of making the local ntpd change its reported stratum? Do I have to customize the local oscillator driver to input the health status? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[questions] Re: NTP community feels broken
On Friday, June 17, 2022 at 9:37:15 AM UTC-4, chris wrote: > The problem is the monitoring software What software product/program do you mean? -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
[questions] Re: NTP community feels broken
On Friday, June 17, 2022 at 11:24:31 AM UTC-4, chris wrote: > It's the code that polls ntp servers to verify that they are up. Where is it in this tarball: http://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p15.tar.gz If it's not there then you're probably in the wrong list/group. -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
[questions] Re: NTP community feels broken
On Friday, June 17, 2022 at 2:24:05 PM UTC-4, chris wrote: > That's correct, but the various issues with the system have been > discussed for years, yet nothing ever gets done about it. That's the > point that Philip above was making... Of course working with Harlan is difficult. Coming here to advise us of that won't result in any changes. Fortunately there are alternatives so there's no need to fret about the "reference" implementation. The issue with your posts is that they were confusing. Or wrong. -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
[questions] Re: NTP community feels broken
On Friday, June 17, 2022 at 2:12:52 PM UTC-4, chris wrote: > Nothing to do with products. ntp.org has a monitoring system that polls > every server in its database to verify that it's reachable. Perhaps you mean pool.ntp.org. It's in the ntp.org namespace but it's a separate project run by Ask Bjørn Hansen. -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
[questions] Re: NTP community feels broken
On Friday, June 17, 2022 at 2:33:35 PM UTC-4, David Woolley wrote: > On 17/06/2022 19:14, Paul G wrote: > > Where is it in this > > tarball:http://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p15.tar.gz > > > > > > If it's not there then you're probably in the wrong list/group. > This group is about the NTP protocol I said probably because other major projects have (or should have) their own discussion channels. -- This is questions@lists.ntp.org Subscribe: questions+subscr...@lists.ntp.org Unsubscribe: questions+unsubscr...@lists.ntp.org
Re: [ntp:questions] lots of GPS modules and info at SparkFun
Figure I might chime in with the gps unit I got and if your in Aust i think its probably about the best deals i've seen that has a pps line (theres also another one they have if you can do smd soldering thats cheaper again). http://www.twig.com.au/store/product_info.php?products_id=108osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4 http://www.twig.com.au/store/product_info.php?products_id=108osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4 I was looking to put together the dirt-cheapest ntpd machine with pps i could, and that was the cheapest i could find (though i havent had the time to put mine together as yet because the pps line does need some soldering). I also happened to have a wyse terminal (x86 based) http://www.wyse.com/products/hardware/thinclients/S10/index.asp that i picked up for around 30$ (currently running ubuntu 10.10 server without too much drama). On 13/02/12 13:00, Dave Hart wrote: On Sat, Feb 11, 2012 at 10:20, Terje Mathisen wrote: unruh wrote: GEt the manual from Mediatex MTK NMEA Packet User Manual, which gives a far far more extensive set of nmea programming instructions for the chipset that Sure uses. Does that one have more info than my current program? C:\c2\nmea-mtkRelease\nmea-mtk.exe -? nmea-mtk (c) 2011 Terje Mathisen Syntax: nmea-mtk [options] The SURE electronics unit people have been buying as an affordable refclock for those with soldering skills and time is the reference design for the SkyNet SKG16AH chip known as SKG16B [1]. Unruh and Terje are talking about a MTK (I or II?) chipset. Does anyone know the relationship between the two? I'm wondering if there's a way to refer to both unambiguously, or if they're subtly different beasts. After a little more digging I came across a nice comparison table of chipsets [2] which suggests to me the SKG16AH is derived from or clones the interface of a MTk design. If you have additional insight or can correct me, I'd appreciate it. [1] http://www.skylab.com.cn/datasheet/SkyNav_SKG16AH_DS.pdf [2] http://wiki.openstreetmap.org/wiki/GPS_Chipset Cheers, Dave Hart ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] ntp on ubuntu 12.10 with gps and pps.
Hi All, I've got a SiRF star 3 GPS with a PPS line which im trying to get running on a machine with ubuntu 12.10 and a serial port using the DCD line for pps signalling. Took quite a while as the ntpd that ships with ubuntu 12.10 appears to be compiled without pps support (please correct me if im wrong here - but no matter what I do, the shipped version never tries to open /dev/pps0, gpspps0, etc etc and i've checked permissions and apparmor) - also theres alot of contradictory info on the net about how you get pps and gps operating this way (took some time to find that i needed flag1 1 in the gps settings - which alot of articles dont mention). But, once it was up and running it appeared to work very well, after a few hours the jitter was down to below 0.01. Next I added in a few external time sources, and i ended up with this: remote refid st t when poll reach delay offset jitter == 203.0.178.191 216.218.254.202 2 u 14 6438.704 990.003 0.189 (my isp) 203.82.209.217 18.26.4.105 2 u 18 643 62.372 997.624 0.466 (pool server) 202.127.210.36 223.255.185.22 u 19 643 22.454 1067.75 1.747 (pool server) 130.102.2.123 130.102.132.164 2 u 17 643 22.947 1000.23 0.392 (pool server) 202.125.45.77 223.252.32.9 2 u 17 643 24.810 1001.95 0.849 (pool server) *127.127.20.0.GPS.0 l78 3770.000 0.467 0.209 (GPS) Everythings almost exactly 1 second out. Reading around about this, it appears that this occurs cause theres possibly too many sentences coming across the 4800 baud serial line, is that correct? After adjusting fudge time2, i ended up with with this: remote refid st t when poll reach delay offset jitter == -203.0.178.191 216.218.254.202 2 u 51 64 3779.070 -5.518 1.423 -202.127.210.36 223.255.185.22 u 53 64 377 21.729 74.408 4.701 *203.192.179.99 223.252.32.9 2 u 48 64 377 22.956 17.581 3.551 +119.148.67.183 203.12.160.2 3 u 51 64 377 21.200 4.094 1.439 +203.192.179.98 203.35.83.2422 u 50 64 377 22.735 17.913 27.315 o127.127.20.0.GPS.0 l38 3770.000 5.080 0.193 and a few hours later: remote refid st t when poll reach delay offset jitter == +203.0.178.191 216.218.254.202 2 u 44 64 3779.041 -10.309 0.356 +202.127.210.36 223.255.185.22 u 50 64 377 21.547 64.812 6.039 +203.192.179.99 210.9.192.50 2 u 35 64 377 23.000 -0.256 2.525 -119.148.67.183 203.12.160.2 3 u 48 64 377 21.006 -15.580 4.364 -203.192.179.98 203.35.83.2422 u 49 64 377 23.130 74.392 26.231 o127.127.20.0.GPS.0 l48 3770.000 -0.065 0.003 and the config i've ended up with is: server 127.127.20.0 mode 1 minpoll 2 maxpoll 4 prefer fudge 127.127.20.0 flag1 1 flag2 0 flag3 1 time2 1.0 Seems like a pretty decent little gps unit, assuming i've got it functioning and configured correctly? ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp on ubuntu 12.10 with gps and pps.
Im running an intel atom also (old one, d945gclf2 board), and its only doing ntp at the moment with a fairly minimal 64bit ubuntu 12.10 server. after 24 hours its now looking like this: remote refid st t when poll reach delay offset jitter == +203.0.178.191 43.128.117.842 u 38 64 3778.960 -11.714 0.169 *27.54.95.12 218.100.43.702 u 31 64 377 61.301 -1.256 0.246 -202.6.248.7 130.102.128.23 3 u 46 64 3779.529 -0.273 0.160 -116.66.162.4130.234.255.83 2 u 52 64 377 20.386 15.747 1.988 +121.0.0.41 204.152.184.72 2 u 59 64 377 25.295 -4.202 3.760 o127.127.20.0.GPS.0 l18 3770.000 -0.001 0.001 I've just tuned the gps so that its only outputing a single nmea sentence (GPZDA) and increased the speed to 9600 and now its no longer needing the fudge factor. Ultimately though, i'll want to try get it running from a geode based machine (which has some seriously low specs, but it'll be amusing to see how it performs). Something else i've noticed as well when im watching it, when it adjusts the system time it seems to impact the jitter calculation quite considerably and with the other ntp servers in there, it doesnt always seem to want to choose the gps as the absolute truth. On 07/04/13 23:46, David Taylor wrote: On 07/04/2013 11:14, Paul J R wrote: Hi All, I've got a SiRF star 3 GPS with a PPS line which im trying to get running on a machine with ubuntu 12.10 and a serial port using the DCD line for pps signalling. [] o127.127.20.0.GPS.0 l 48 3770.000 -0.065 0.003 [] Seems like a pretty decent little gps unit, assuming i've got it functioning and configured correctly? Just for comparison: Intel Atom PC running FreeBSD 8.2 (Pixie): o127.127.20.1.PPS. offset/jitter -0.001 0.002 Two Raspberry Pis running Linux 3.2.27+ o127.127.22.0.PPS. offset/jitter 0.002 0.002 o127.127.22.0.PPS. offset/jitter 0.001 0.002 Raspberry Pi running Linux 3.36.11 o127.127.22.0.PPS. offset/jitter 0.000 0.002 65 microseconds offset seems a little high to me, but the PCs I've just quoted are all (mostly) /only/ serving NTP. I have been doing a little installation work on Raspberry Pi #3 today, and it now has a steady CPU and network I/O load. Its PPS was only configured yesterday. Performance graphs are here: http://www.satsignal.eu/mrtg/performance_ntp.php I hope that helps your comparisons. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] Atheros AR9331 w/GPS + PPS
Hi All, Thought I might share my experiences. Got given a little AR9331 based router some months ago (gl.inet 6416a) and spun up pps on one of its gpio lines. Its been running for about 2 months and so far the performance of it has been quite impressive from a client perspective. Havent seen many references to anyone using an Atheros chipset for pps and ntp so far but im curious if anyone else has had any experiences? Regards, Paul ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Atheros AR9331 w/GPS + PPS
On 8/09/2015 5:44 pm, Gabs Ricalde wrote: On Tue, Sep 1, 2015 at 3:22 AM, Paul J R <m...@pjr.cc> wrote: Hi All, Thought I might share my experiences. Got given a little AR9331 based router some months ago (gl.inet 6416a) and spun up pps on one of its gpio lines. Its been running for about 2 months and so far the performance of it has been quite impressive from a client perspective. Havent seen many references to anyone using an Atheros chipset for pps and ntp so far but im curious if anyone else has had any experiences? Regards, Paul I've been running two devices (TPLink WR703N, MR3020) for more than 2 years with almost no issue. Also impressed on what these devices could do. Does the new OpenWRT versions have the PPS driver for AR9331? I had to use this for Attitude Adjustment: https://code.google.com/p/openwrt-stratum1/ The GL.iNet looks like it's made for hacking, wish it's sold locally. Yeah, i did stumble onto the code on the google, but i ended up writing a new driver myself as that one was polling based. There was a patch (https://github.com/GBert/openwrt-misc/tree/master/gpio-test/src) which adds interrupt based gpio support, so i wrote a patch to add pps-gpio on top of that (https://dl.dropboxusercontent.com/u/49959760/970-pps-gpio-ar9331.patch). Its an openwrt patch specifically for the gl.inet board, but the code is pretty straight forward (though a bit messy) and should work on any ar9331 based box. It'll work on 14.07 and above (though i've only tested compiling it against 14.07 and the current trunk code) I've also tested it with a som9331 openembed board and it seems to work quite well on that as well. Not sure what locally would be for you, but if your in the US, there is a 1-day shipping option (i believe) for that particular box on amazon. To give an idea on size though (which is perhaps what impressed me most), here it is next to an RPI2 https://dl.dropboxusercontent.com/u/49959760/IMG_20150904_014715_w.jpg and im very tempted to make a little waterproof box for it, a poe splitter and stick it to the roof somewhere as the components i've looked at in it all have fairly extreme environment ratings. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] More than one PPS source on Raspberry Pi?
The answer is no and yes (and also maybe).. no because the current pps-gpio driver only loads a single pin (though it could be extended to load more than one, but i dont think anyones done that). yes because the other way it could be achieved is to create a second module called pps-gpio2 and then init that with a different pin config, and that wouldn't be overly hard and possibly easier than trying to extend the existing driver (depending on knowledge of kernel drivers). Lastly, maybe because im unaware of what hardware limits the rpi might have which might get in the way of doing something like that (from what i've read, every pin is capable of being configured for interrupts, so it sounds like it should be possible) On 05/12/17 03:35, Frank Wayne wrote: Has anyone tried to use more than one PPS source at the same time on a Raspberry Pi? The device tree overlay pps-gpio does not seem to support more than one instance. That is, if my config.txt specifies two instances of pps-gpio for different GPIO pins, only /dev/pps0 is created. The documentation for pps_gpio is limited or missing, and the Raspberry Pi forum and the LinuxPPS list have not helped. If pps-gpio cannot do it, is there another way to get PPS devices for Raspbian or another OS that will run on a Pi? Frank Wayne ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
