From: Bill Fink <billfink@mindspring.com>
To: Gabriel Paubert <paubert@iram.es>
Cc: linuxppc-dev@lists.linuxppc.org, Bill Fink <billfink@mindspring.com>
Subject: Re: Time precision, adjtime(x) vs. gettimeofday
Date: Fri, 10 Oct 2003 12:39:04 -0400 [thread overview]
Message-ID: <20031010123904.24a8c6cd.billfink@mindspring.com> (raw)
In-Reply-To: <20031010073314.GA14632@iram.es>
On Fri, 10 Oct 2003, Gabriel Paubert wrote:
> On Fri, Oct 10, 2003 at 01:12:54AM -0400, Bill Fink wrote:
> >
> > This discussion prompted me to finally ask about another clock related
> > problem I see on the 867 MHz G4 systems at work. The clocks on these
> > systems continuously run 0.2% slow (about 3 minutes per day). Apparently
> > this is more than ntp can adjust for (using scaling), as I get many of
> > these error messages in the log:
>
> Indeed, the limit of NTP is about 500ppm (0.05%) AFAIR. Anything higher
> and you go into period time steps like the one you report.
>
> 2.4.20 is recent enough and should not have this kind of problems.
>
> What is the initial decrementer frequency from boot messages log?
clifford% dmesg | grep -i decr
time_init: decrementer frequency = 33.290001 MHz
> What is the timebase frequency from OF?
> (od -td4 /proc/device-tree/cpus/PowerPC,G4/timebase-frequency)
clifford% od -td4 /proc/device-tree/cpus/PowerPC,G4/timebase-frequency
0000000 33290001
0000004
-Bill
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-10-10 16:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-10 5:12 Time precision, adjtime(x) vs. gettimeofday Bill Fink
2003-10-10 7:33 ` Gabriel Paubert
2003-10-10 16:39 ` Bill Fink [this message]
2003-10-10 7:53 ` Ethan Benson
-- strict thread matches above, loose matches on Subject: below --
2003-10-11 4:45 Bill Fink
2003-10-11 5:27 ` Ethan Benson
2003-10-11 14:58 ` Benjamin Herrenschmidt
2003-10-14 7:07 ` Gabriel Paubert
2003-10-14 11:16 ` Benjamin Herrenschmidt
2003-10-08 13:32 Benjamin Herrenschmidt
2003-10-08 15:48 ` Gabriel Paubert
2003-10-08 16:22 ` Benjamin Herrenschmidt
2003-10-08 17:50 ` Gabriel Paubert
2003-10-08 18:22 ` Benjamin Herrenschmidt
2003-10-08 22:17 ` Pavel Machek
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