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From: Ingo Molnar <mingo@elte.hu>
To: john stultz <johnstul@us.ibm.com>
Cc: Frank Sorenson <frank@tuxrocks.com>,
	lkml <linux-kernel@vger.kernel.org>,
	Darren Hart <dvhltc@us.ibm.com>,
	Nishanth Aravamudan <nacc@us.ibm.com>,
	George Anzinger <george@mvista.com>,
	Roman Zippel <zippel@linux-m68k.org>,
	Ulrich Windl <ulrich.windl@rz.uni-regensburg.de>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/13] Time: Generic Timeofday Subsystem (v B10)
Date: Tue, 15 Nov 2005 21:53:55 +0100	[thread overview]
Message-ID: <20051115205355.GA20885@elte.hu> (raw)
In-Reply-To: <1132084415.2906.12.camel@leatherman>


* john stultz <johnstul@us.ibm.com> wrote:

> > idle=poll does seem to fix the major clock drift problem.  There may
> > still be an issue, but it's much smaller:
> > 
> > 2.6.14-mm2-todb10:
> > 14 Nov 21:50:57      offset: -0.025373       drift: -22404.0 ppm
> > 14 Nov 21:51:59      offset: -1.577053       drift: -24985.4603175 ppm
> > 14 Nov 21:53:00      offset: -3.104569       drift: -25012.9032258 ppm
> > 
> > 2.6.14-mm2-todb10 with idle=poll:
> > 14 Nov 21:37:59      offset: 5.9e-05         drift: 63.0 ppm
> > 14 Nov 21:39:00      offset: 0.003207        drift: 51.7903225806 ppm
> 
> Hmm. It seems the c3 compensation is triggering when it shouldn't, or 
> maybe its over compensating.
> 
> I can't reproduce it on my laptop. Do you recall if in previous tests 
> you saw anything like this? I'm trying to narrow down if its just a 
> difference in hardware or if something in the c3 idle code changed.

it's with an earlier queue of yours, but maybe it's related: i have a 
report that HPET causes HRT inaccuracies (e.g. sleeps for 20 msecs last 
21 msecs). If all HPET options are turned off in the .config then 
everything is fine and accurate.

	Ingo

  reply	other threads:[~2005-11-15 20:54 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-12  4:48 [PATCH 0/13] Time: Generic Timeofday Subsystem (v B10) john stultz
2005-11-12  4:48 ` [PATCH 1/13] Time: Reduced NTP rework (part 1) john stultz
2005-11-12  4:49 ` [PATCH 2/13] Time: Reduced NTP Rework (part 2) john stultz
2005-11-12  4:49 ` [PATCH 3/13] Time: Clocksource Infrastructure john stultz
2005-11-12  4:49 ` [PATCH 4/13] Time: Generic Timekeeping Infrastructure john stultz
2005-11-12  4:49 ` [PATCH 5/13] Time: i386 Conversion - part 1: Move timer_pit.c to i8253.c john stultz
2005-11-12  4:49 ` [PATCH 6/13] Time: i386 Conversion - part 2: Move timer_tsc.c to tsc.c john stultz
2005-11-12  4:49 ` [PATCH 7/13] Time: i386 Conversion - part 3: Rework TSC Support john stultz
2005-11-12  4:49 ` [PATCH 8/13] Time: i386 Conversion - part 4: ACPI PM variable renaming john stultz
2005-11-12  4:49 ` [PATCH 9/13] Time: i386 Conversion - part 5: Enable Generic Timekeeping john stultz
2005-11-12  4:49 ` [PATCH 10/13] Time: i386 Conversion - part 6: Remove Old Code john stultz
2005-11-12  4:50 ` [PATCH 11/13] Time: x86-64 Conversion to Generic Timekeeping john stultz
2005-11-12  4:50 ` [PATCH 12/13] Time: i386/x86-64 Clocksource Drivers john stultz
2005-11-12  4:50 ` [PATCH 13/13] Time: Generic Timekeeping Paraniod Debug Patch john stultz
2005-11-13  1:24 ` [PATCH 0/13] Time: Generic Timeofday Subsystem (v B10) Andi Kleen
2005-11-13  2:34   ` john stultz
2005-11-13  7:32   ` Ingo Molnar
2005-11-13 10:53     ` Andi Kleen
2005-11-14 17:41       ` john stultz
2005-11-14 18:23       ` Ingo Molnar
2005-11-14 21:22 ` Frank Sorenson
2005-11-14 21:38   ` john stultz
2005-11-14 21:53     ` Frank Sorenson
2005-11-14 22:02       ` john stultz
2005-11-14 23:07         ` Frank Sorenson
2005-11-14 23:25           ` john stultz
2005-11-15  5:04             ` Frank Sorenson
2005-11-15 19:53               ` john stultz
2005-11-15 20:53                 ` Ingo Molnar [this message]
2005-11-15 21:04                   ` john stultz

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