[ntp:hackers] Of Linux and jitter
David L. Mills
mills at udel.edu
Tue Oct 19 13:00:16 PDT 2004
We have a lot of Ultra 10s around here and are about to upgrade pogo.
The staff saays we will upgrade to 10 when it is officially announced;
however, I'll see if it can happen quicker for at least one of my
Solariba. Thanks for the tip.
Brian Utterback wrote:
> I would suggest that you upgrade or at least dual boot the Blade to use
> Solaris 10. The Dtrace facility makes debugging this kind of problem
> pretty simple. Unfortunately, the Ultra-1 will not run Solaris 10, much
> to my chagrin.
> David L. Mills wrote:
>> 1. All the backroom and campus machines are now running ntp-dev and
>> all seem to work except Linux albert on the campus wire. It segfaults
>> after a few minutes. I am dumb with Linux debugging tools, so I'll
>> leave the carcass on the hope some Linux jockey can look at it.
>> 2. I'm very suspicious about the Solaris jitter using a serial port
>> and any of several radios. The jitter can be over one second(!) and
>> varies in intensity with time. I can't believe the port interrupt
>> routine can have jitter that high. The jitter does not occur with a
>> SunOS SPARC IPC running ntp-dev, which is now the best timekeeper we
>> have. The jitter first showed up on Ultra-1 pogo running Solaris 8/9
>> and Blade 1500 running Solaris 9. Could there be something in the
>> ntpd I/O code causing this? It's only in the serial port code; there
>> is no such jitter in the packet I/O code.
>> hackers mailing list
>> hackers at support.ntp.org
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