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From: Theo Veenker <Theo.Veenker@domain.hid>
To: Xenomai <xenomai@xenomai.org>
Subject: [Xenomai-help] accuracy of system clock
Date: Mon, 19 Nov 2007 10:29:42 +0100	[thread overview]
Message-ID: <47415786.6040208@domain.hid> (raw)

Hi all,

I'm using clock_gettime(REALTIME,&t) in a kernel module (posix skin) to
timestamp something. I know accessing this clock from user space yields
values different from those returned by the xenomai posix skin due to
ntpdate. But my concern is that the difference in pace is too much.
On one system it is about 90us/s wrong on another it is 160us/s.

I assume the speed of the ntp corrected clock is more or less correct.
Is there some calibration procedure I can run to tweak xenomai to make
sure in xenomai I get 1e9 ticks per *true* second?
I have enabled CONFIG_X86_UP_APIC.

Theo




             reply	other threads:[~2007-11-19  9:29 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-19  9:29 Theo Veenker [this message]
2007-11-19 15:25 ` [Xenomai-help] accuracy of system clock Gilles Chanteperdrix
2007-11-19 15:46   ` Theo Veenker
2007-11-19 20:54     ` Gilles Chanteperdrix
2007-11-19 15:47   ` Jan Kiszka

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