From: Bill Fink <billfink@mindspring•com>
To: LinuxPPC Developers <linuxppc-dev@lists•linuxppc.org>
Cc: Bill Fink <billfink@mindspring•com>
Subject: Re: Time precision, adjtime(x) vs. gettimeofday
Date: Sat, 11 Oct 2003 00:45:41 -0400 [thread overview]
Message-ID: <20031011004541.5eda8953.billfink@mindspring.com> (raw)
On Thu, 9 Oct 2003, Ethan Benson 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:
>
> is it a quicksilver G4? i maintain one of those and its time goes off
> much faster then that (3 minutes within a couple hours).
Yes I believe it's a quicksilver G4.
clifford% cat /proc/cpuinfo
cpu : 7450, altivec supported
clock : 866MHz
revision : 2.1 (pvr 8000 0201)
bogomips : 865.07
machine : PowerMac3,5
motherboard : PowerMac3,5 MacRISC2 MacRISC Power Macintosh
detected as : 69 (PowerMac G4 Silver)
pmac flags : 00000000
L2 cache : 256K unified
memory : 640MB
pmac-generation : NewWorld
> the fix is rather simple:
>
> --- linux.old/arch/ppc/platforms/pmac_time.c.orig Sat Nov 30 02:33:49 2002
> +++ linux/arch/ppc/platforms/pmac_time.c Sat Nov 30 02:33:22 2002
> @@ -262,7 +262,9 @@
> * calibration. That's better since the VIA itself seems
> * to be slightly off. --BenH
> */
> +#if 0
> if (!machine_is_compatible("MacRISC2"))
> +#endif
> if (via_calibrate_decr())
> return;
Thanks for the suggested fix. I'll give it a try when I get a chance.
> in the case of the quicksilver VIA is FAR better then whatever it uses
> instead.
Assuming the fix works, is there a simple way to test for the
quickserver G4 model rather than doing the "#if 0", since I like
to run a common kernel across a variety of different processor
models.
-Bill
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next reply other threads:[~2003-10-11 4:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-11 4:45 Bill Fink [this message]
2003-10-11 5:27 ` Time precision, adjtime(x) vs. gettimeofday Ethan Benson
2003-10-11 14:58 ` Benjamin Herrenschmidt
2003-10-14 7:07 ` Gabriel Paubert
2003-10-14 11:16 ` Benjamin Herrenschmidt
-- strict thread matches above, loose matches on Subject: below --
2003-10-10 5:12 Bill Fink
2003-10-10 7:33 ` Gabriel Paubert
2003-10-10 16:39 ` Bill Fink
2003-10-10 7:53 ` Ethan Benson
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