unruh wrote:
On 2010-03-11, Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net wrote:
Modern Linux kernels don't support PPS in the sense of RFC-whateveritis.
There is support for an ioctl that says wake me up when a modem signal
changes.
gpsd uses that to provide PPS support. I don't
David Woolley wrote:
So? The interrupt still takes the same time to be activated. On a GHZ
system, there is enough time in 1usec to run 1000 commands, and it is
hard to imagine that many being used to return the ioctl. I have worried
That's 1000 machine cycles, not 1000 instructions. On modern
David Woolley wrote:
That's 1000 machine cycles, not 1000 instructions. On modern systems,
I'm not sure that 1000 cycles isn't a typical time for a system call on
modern, high level language progammed, bloatware. (I seem to remember
hand coding an ISR in assembler to a budget of 100
On 2010-03-12, David Woolley da...@ex.djwhome.demon.invalid wrote:
unruh wrote:
On 2010-03-11, Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net wrote:
Modern Linux kernels don't support PPS in the sense of RFC-whateveritis.
There is support for an ioctl that says wake me up when a modem
unruh wrote:
On 2010-03-12, David Woolley da...@ex.djwhome.demon.invalid wrote:
unruh wrote:
On 2010-03-11, Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net wrote:
Modern Linux kernels don't support PPS in the sense of RFC-whateveritis.
There is support for an ioctl that says wake me
unruh wrote:
On 2010-03-12, Terje Mathisenterje.mathisen at tmsw.no wrote:
OTOH, I have personally never seen this on any of my S1 servers which
all use the serial port.
Not sure how you would see that. If the interrupt were delayed by one
ms ntp would not know. It would see something only
On 2010-03-12, Uwe Klein uwe_klein_habertw...@t-online.de wrote:
unruh wrote:
On 2010-03-12, David Woolley da...@ex.djwhome.demon.invalid wrote:
unruh wrote:
On 2010-03-11, Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net
wrote:
Modern Linux kernels don't support PPS in the sense of
unruh wrote:
I cerainly would not rely on the data in/out for the interrupt as it
might well have clock aliasing. But is there not a specific pin on the
serial port which is an immediate interrupt pin like the interrupt pin
on the parallel port?
The hardware supports interrupt on DCD, DTR,
John Hasler wrote:
David writes:
My report to chrony-dev list, along with links to mrtg graphs, never
made it to the list, and although I can send that again...
Please send it directly to me.
OK it was a few months back, I'll try to find it and make sure
links to the graphs still work.
Richard B. Gilbert wrote:
Chuck Swiger wrote:
On Mar 10, 2010, at 1:05 PM, John Hasler wrote:
I gather that crony is intended for machines with infrequent network
connections.
That was one of the goals when it was first developed ten years ago. It
has gone far beyond that now.
OK.
I can't
On Wed, Mar 10, 2010 at 03:25:45PM -, David J Taylor wrote:
- and one for Bill, how much better might chrony be than official NTP?
In my experience, chrony is about 3-20 times better than NTP when using
the same poll interval. The more stable is temperature and CPU load the
smaller is the
On Thu, Mar 11, 2010 at 11:53:28AM +, David Lord wrote:
In 1997, before I'd used ntpd I had chrony on a pair of systems
used for dialup connections peered together. Later, ntpd on my
servers worked without any problem using the two chrony sources.
I've not been able to successfully peer
Miroslav Lichvar mlich...@redhat.com wrote in message
news:20100311124036.ga22...@localhost...
[]
I did a NTP vs chrony comparison last June with GPS 18x LVC in an
office environment, clock drift was moving in about 0.8ppm range. Here
are distributions of PPS samples received from gpsd:
Miroslav Lichvar wrote:
On Thu, Mar 11, 2010 at 11:53:28AM +, David Lord wrote:
In 1997, before I'd used ntpd I had chrony on a pair of systems
used for dialup connections peered together. Later, ntpd on my
servers worked without any problem using the two chrony sources.
I've not been able
David J Taylor wrote:
Miroslav Lichvar mlich...@redhat.com wrote in message
news:20100311124036.ga22...@localhost...
[]
I did a NTP vs chrony comparison last June with GPS 18x LVC in an
office environment, clock drift was moving in about 0.8ppm range. Here
are distributions of PPS samples
Once upon a time, Miroslav Lichvar mlich...@redhat.com said:
As for PPS source, LinuxPPS patch can be applied to kernel (hopefully
it will be merged into mainline soon), or PPS samples from gpsd can be
used instead, versions 2.90 and later works best.
There's also the user-space shmpps (which is
David J Taylor wrote:
Miroslav Lichvar mlich...@redhat.com wrote in message
news:20100311124036.ga22...@localhost...
[]
I did a NTP vs chrony comparison last June with GPS 18x LVC in an
office environment, clock drift was moving in about 0.8ppm range. Here
are distributions of PPS samples
David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions,
but I'm now considering a dual-core Intel Atom system, which is
Compatible with Linux according the the very minimal blurb I have
right now. If the system is to be used purely for NTP with Linux as a
Uwe Klein wrote:
And now for something completely different:
Build your own ( possibly cross platform ) mini/embedded/single purpose
linux distribution:
http://en.opensuse.org/Build_Service
uwe
forgot this:
http://susestudio.com/
___
On 2010-03-11, Richard B. Gilbert rgilber...@comcast.net wrote:
David J Taylor wrote:
Miroslav Lichvar mlich...@redhat.com wrote in message
news:20100311124036.ga22...@localhost...
[]
I did a NTP vs chrony comparison last June with GPS 18x LVC in an
office environment, clock drift was
Modern Linux kernels don't support PPS in the sense of RFC-whateveritis.
There is support for an ioctl that says wake me up when a modem signal
changes.
gpsd uses that to provide PPS support. I don't have any data.
I believe but am not sure, that that uses an interrupt.
I think so. But
On 2010-03-11, Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net wrote:
Modern Linux kernels don't support PPS in the sense of RFC-whateveritis.
There is support for an ioctl that says wake me up when a modem signal
changes.
gpsd uses that to provide PPS support. I don't have any data.
unruh wrote:
[snip]
time that the serial port ioctl returned. I know on my parallel port
interrupt, the test I ran showed that the time between activating the
pin on the parallel port and the parallel port interrupt service routine
timestamping the interrupt was of the order of 1usec. It would
Yes, I know it's one of those low long is a piece of string questions, but
I'm now considering a dual-core Intel Atom system, which is Compatible
with Linux according the the very minimal blurb I have right now. If the
system is to be used purely for NTP with Linux as a serial-port GPS/PPS
Once upon a time, David J Taylor david-tay...@blueyonder.co.uk said:
Yes, I know it's one of those low long is a piece of string questions, but
I'm now considering a dual-core Intel Atom system, which is Compatible
with Linux according the the very minimal blurb I have right now.
Fedora 12 i686
David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions,
but I'm now considering a dual-core Intel Atom system, which is
Compatible with Linux according the the very minimal blurb I have
right now. If the system is to be used purely for NTP with Linux as a
David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions,
but I'm now considering a dual-core Intel Atom system, which is
Compatible with Linux according the the very minimal blurb I have
right now. If the system is to be used purely for NTP with Linux as a
David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions,
but I'm now considering a dual-core Intel Atom system, which is
Compatible with Linux according the the very minimal blurb I have
right now. If the system is to be used purely for NTP with Linux as a
On Mar 10, 2010, at 7:25 AM, David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions, but
I'm now considering a dual-core Intel Atom system, which is Compatible with
Linux according the the very minimal blurb I have right now. If the system
is to be used
On 2010-03-10, Matt Nordhoff mnordh...@mattnordhoff.com wrote:
If you're into using development releases of NTP, it's worth noting
that there are Debian packages available, so you don't have to compile
your own:
http://packages.ntp.org/debian/
(Although I don't use Debian Lenny myself, so I
On 2010-03-10, David Lord sn...@lordynet.org wrote:
David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string questions,
but I'm now considering a dual-core Intel Atom system, which is
Compatible with Linux according the the very minimal blurb I have
right now. If
From: Chuck Swiger cswi...@mac.com
Date: Wed, 10 Mar 2010 09:32:21 -0800
Sender: questions-bounces+oberman=es@lists.ntp.org
On Mar 10, 2010, at 7:25 AM, David J Taylor wrote:
Yes, I know it's one of those low long is a piece of string
questions, but I'm now considering a dual-core
Chuck Swiger writes:
I gather that crony is intended for machines with infrequent network
connections.
That was one of the goals when it was first developed ten years ago. It
has gone far beyond that now.
I can't imagine trying to run it for a permanently networked stratum-1
timesource.
On Mar 10, 2010, at 1:05 PM, John Hasler wrote:
I gather that crony is intended for machines with infrequent network
connections.
That was one of the goals when it was first developed ten years ago. It
has gone far beyond that now.
OK.
I can't imagine trying to run it for a permanently
unruh wrote:
On 2010-03-10, David Lord sn...@lordynet.org wrote:
If you don't already know Linux well already then I'd suggest
FreeBSD as being a more solid base than a Linux distribution.
Only lightweight Linux I've tried recently is Slackware which
seemed in many ways similar to BSD
Chuck Swiger wrote:
On Mar 10, 2010, at 1:05 PM, John Hasler wrote:
I gather that crony is intended for machines with infrequent network
connections.
That was one of the goals when it was first developed ten years ago. It
has gone far beyond that now.
OK.
I can't imagine trying to run it
On 2010-03-10, Richard B. Gilbert rgilber...@comcast.net wrote:
Chuck Swiger wrote:
On Mar 10, 2010, at 1:05 PM, John Hasler wrote:
I gather that crony is intended for machines with infrequent network
connections.
That was one of the goals when it was first developed ten years ago. It
has
On Mar 10, 2010, at 4:59 PM, unruh wrote:
I've seen monitoring data from the NTP pool project for people using other
NTP implementations, and they don't seem to be nearly as reliable
timesources as the original ntpd implementation. It's not just my opinion:
Uh, just because alternative X
On 2010-03-11, Chuck Swiger cswi...@mac.com wrote:
On Mar 10, 2010, at 4:59 PM, unruh wrote:
?? How would we know, especially since David Mills says they can
detect implimentations like chrony and get them out of the pool.
That seems to be a strange thing for David Mills to say, as Ask
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