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From: Andrea Arcangeli <andrea@suse.de>
To: Pavel Machek <pavel@suse.cz>
Cc: john stultz <johnstul@us.ibm.com>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Con Kolivas <kernel@kolivas.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: dynamic-hz
Date: Tue, 14 Dec 2004 03:04:25 +0100	[thread overview]
Message-ID: <20041214020425.GS16322@dualathlon.random> (raw)
In-Reply-To: <20041213204933.GA4693@elf.ucw.cz>

On Mon, Dec 13, 2004 at 09:49:33PM +0100, Pavel Machek wrote:
> Yes, it was supposed to be simple, so that Andrea understands that
> there's nothing inherently broken with single-shot timers.

Single shot timer is unusable for system time accounting, at least as
long as you want to allow nmi. This is a tangible fact, no matter how
simple the example is.

Even the lost tick compensation is not working at all, and it has the
same issues that the one-shot timer has in keeping the system time
accurate.

Pavel, write a program to do iopl(2) cli() wait 3msec; sti() wait 3msec
cli() wait 3msec in a loop. Then watch your system time go in the future
at a rate of a few minutes per hour, then fix it. After you fixed it
we'll get my attention about one-shot timer again ;). I already tried to
fix it and failed so far since I can't see bugs in the current code.
(actually I fixed it by breaking the code, and dropping some ticks
somewhere)

  reply	other threads:[~2004-12-14  2:08 UTC|newest]

Thread overview: 126+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-11 14:23 dynamic-hz Andrea Arcangeli
2004-12-11 14:50 ` dynamic-hz Zwane Mwaikambo
2004-12-12  6:57   ` dynamic-hz Andrea Arcangeli
2004-12-11 21:41 ` dynamic-hz Jan Engelhardt
2004-12-12 16:35 ` dynamic-hz Pavel Machek
2004-12-12 22:23   ` dynamic-hz Andrea Arcangeli
2004-12-12 23:36     ` dynamic-hz Con Kolivas
2004-12-12 23:42       ` dynamic-hz Pavel Machek
2004-12-13  0:09         ` dynamic-hz Con Kolivas
2004-12-13  8:37           ` dynamic-hz Jan Engelhardt
2004-12-13 10:43           ` dynamic-hz Pavel Machek
2004-12-13 11:08             ` dynamic-hz Andrea Arcangeli
2004-12-13 19:36               ` dynamic-hz john stultz
2004-12-12 23:43       ` dynamic-hz Andrea Arcangeli
2004-12-13  0:18         ` dynamic-hz Con Kolivas
2004-12-13  0:27           ` dynamic-hz Andrea Arcangeli
2004-12-13  1:50             ` dynamic-hz Zwane Mwaikambo
2004-12-13 11:28               ` dynamic-hz Andrea Arcangeli
2004-12-13 12:43                 ` dynamic-hz Pavel Machek
2004-12-13 12:58                   ` dynamic-hz Andrea Arcangeli
2004-12-13 19:12                     ` dynamic-hz Pavel Machek
2004-12-13 20:34                       ` dynamic-hz john stultz
2004-12-13 20:49                         ` dynamic-hz Pavel Machek
2004-12-14  2:04                           ` Andrea Arcangeli [this message]
     [not found]                           ` <20041214013924.GB14617@atomide.com>
2004-12-14  9:37                             ` dynamic-hz Pavel Machek
2004-12-14 21:18                               ` dynamic-hz Tony Lindgren
2004-12-14 22:06                                 ` dynamic-hz Pavel Machek
2004-12-14 23:00                                   ` dynamic-hz linux-os
2004-12-14 23:13                                     ` dynamic-hz Tony Lindgren
2004-12-22 20:02                                       ` dynamic-hz Tony Lindgren
2004-12-14 23:04                                   ` dynamic-hz Tony Lindgren
2004-12-14  2:46                         ` dynamic-hz Andrea Arcangeli
2004-12-14 19:24                           ` dynamic-hz john stultz
2004-12-14  2:36                       ` dynamic-hz Andrea Arcangeli
2004-12-14  9:39                         ` dynamic-hz Pavel Machek
2004-12-14  9:59                         ` dynamic-hz Pavel Machek
2004-12-14 15:25                           ` dynamic-hz Andrea Arcangeli
2004-12-14 22:02                             ` USB making time drift [was Re: dynamic-hz] Pavel Machek
2004-12-14 23:16                               ` Andrea Arcangeli
2004-12-15  2:59                                 ` Gene Heskett
2004-12-15  9:17                                   ` Andrea Arcangeli
2004-12-15 16:44                                     ` Gene Heskett
2004-12-15 18:20                                       ` Andrea Arcangeli
2004-12-16  1:59                                         ` Gene Heskett
2004-12-16 11:30                                           ` Andrea Arcangeli
2004-12-16 12:50                                           ` Alan Cox
2004-12-15 20:16                                       ` Pavel Machek
2004-12-16  2:02                                         ` Gene Heskett
2004-12-15 17:03                                     ` Gene Heskett
2004-12-15 17:48                                       ` Tim Schmielau
2004-12-16  2:03                                         ` Gene Heskett
2004-12-16  0:58                                 ` Pavel Machek
2004-12-16  2:33                                   ` john stultz
2004-12-16  1:15                               ` Time goes crazy in 2.6.9 after long cli [was Re: USB making time drift] Pavel Machek
2004-12-16 11:13                                 ` Andrea Arcangeli
2004-12-16 12:49                                   ` Alan Cox
2004-12-13 14:50                 ` dynamic-hz Zwane Mwaikambo
2004-12-13  7:43       ` dynamic-hz Stefan Seyfried
2004-12-13 13:58         ` dynamic-hz Russell King
2004-12-13 14:14           ` dynamic-hz Russell King
2004-12-13 14:52           ` dynamic-hz Alan Cox
2004-12-13 16:23             ` dynamic-hz Russell King
2004-12-13 17:53               ` dynamic-hz Michael Buesch
2004-12-13 18:04                 ` dynamic-hz Russell King
2004-12-13 19:04               ` dynamic-hz Pavel Machek
2004-12-13 20:11               ` dynamic-hz Russell King
2004-12-14  0:16             ` dynamic-hz Eric St-Laurent
2004-12-15 18:04               ` dynamic-hz Alan Cox
2004-12-15 19:54                 ` dynamic-hz linux-os
2004-12-16  2:17                   ` dynamic-hz Gene Heskett
2004-12-16 12:42                     ` dynamic-hz linux-os
2004-12-17 20:12                     ` dynamic-hz H. Peter Anvin
2004-12-16  9:10                 ` dynamic-hz Gabriel Paubert
2004-12-16 12:17                   ` dynamic-hz Geert Uytterhoeven
2004-12-16 14:00                   ` dynamic-hz Mitchell Blank Jr
2004-12-13 15:30           ` dynamic-hz Zwane Mwaikambo
2004-12-13 15:59             ` dynamic-hz Russell King
2004-12-13 16:14               ` dynamic-hz Pavel Machek
2004-12-13 16:06           ` dynamic-hz Pavel Machek
2004-12-13 16:19         ` dynamic-hz Jan Engelhardt
2004-12-13  8:29       ` dynamic-hz Jan Engelhardt
2004-12-14 22:54         ` dynamic-hz Lee Revell
2004-12-14 23:38           ` dynamic-hz Chris Friesen
2004-12-15  8:32             ` dynamic-hz Jan Engelhardt
2004-12-13 11:02       ` dynamic-hz Andrew Morton
2004-12-13 11:17         ` dynamic-hz Andrea Arcangeli
2004-12-13 11:25           ` dynamic-hz Andrew Morton
2004-12-13 11:47             ` dynamic-hz Andrea Arcangeli
2004-12-14  3:56               ` dynamic-hz Nish Aravamudan
2004-12-14  3:54             ` dynamic-hz Nish Aravamudan
2004-12-14  4:29               ` dynamic-hz Andrew Morton
2004-12-14  5:25                 ` dynamic-hz Nish Aravamudan
2004-12-17 20:10                 ` dynamic-hz Nish Aravamudan
2004-12-14 10:01               ` dynamic-hz Domen Puncer
2004-12-14 16:56                 ` dynamic-hz Nish Aravamudan
2004-12-14 14:23               ` dynamic-hz linux-os
2004-12-14 16:54                 ` dynamic-hz Nish Aravamudan
2004-12-14 17:15                   ` dynamic-hz Andrea Arcangeli
2004-12-14 17:42                     ` dynamic-hz Nish Aravamudan
2004-12-14 18:29                       ` dynamic-hz Andrea Arcangeli
2004-12-14 19:00                         ` dynamic-hz Nish Aravamudan
2004-12-14 18:22                     ` dynamic-hz linux-os
2004-12-14 18:38                       ` dynamic-hz Andrea Arcangeli
2004-12-14 18:50                       ` dynamic-hz Pavel Machek
2004-12-13 11:19         ` dynamic-hz Hans Kristian Rosbach
2004-12-13 11:22           ` dynamic-hz Pavel Machek
2004-12-13 11:39             ` dynamic-hz Andrea Arcangeli
2004-12-13 12:51             ` dynamic-hz Hans Kristian Rosbach
2004-12-13 13:01               ` dynamic-hz Andrea Arcangeli
2004-12-13 13:02                 ` dynamic-hz Andrea Arcangeli
2004-12-13 15:06               ` dynamic-hz Geert Uytterhoeven
2004-12-13 16:12                 ` dynamic-hz Pavel Machek
2004-12-13 16:14                   ` dynamic-hz Geert Uytterhoeven
2004-12-14  4:06                   ` dynamic-hz Nish Aravamudan
2004-12-14  4:05               ` dynamic-hz Nish Aravamudan
2004-12-13 11:33           ` dynamic-hz Andrea Arcangeli
2004-12-13 14:38           ` dynamic-hz Zwane Mwaikambo
2004-12-13 12:00       ` dynamic-hz Alan Cox
2004-12-13 15:52         ` dynamic-hz Andrea Arcangeli
2004-12-14 22:28       ` dynamic-hz Lee Revell
2004-12-14 22:40         ` dynamic-hz Con Kolivas
2004-12-14 22:50           ` dynamic-hz Lee Revell
2004-12-13 20:26 ` dynamic-hz Olaf Hering
2004-12-13 22:41   ` dynamic-hz Andrea Arcangeli
2004-12-13 20:56 ` dynamic-hz john stultz
2004-12-13 22:21   ` dynamic-hz Andrea Arcangeli

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