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From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	stable@kernel.org, Greg KH <greg@kroah.com>,
	Chris Wright <chrisw@sous-sol.org>
Subject: Re: [patch] fix the softlockup watchdog to actually work
Date: Thu, 19 Jul 2007 16:50:58 +0200	[thread overview]
Message-ID: <20070719145058.GA11971@elte.hu> (raw)
In-Reply-To: <469F793E.6030006@goop.org>


* Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> Hm, or more specifically, why would that be a problem for softlockup? 
> Do you mean it doesn't measure time during ACPI idle?  That would just 
> make it trigger later than it would otherwise.

no, the return value after idling can be completely random on some 
boxes, on a 64-bit scale - triggering the softlockup watchdog randomly. 
(some boxes return random TSC values, etc.) Again, it's fine for the 
scheduler's purpose, that's why i named it sched_clock().

the proper clocksource use within the kernel is ktime_get() [or 
ktime_get_ts()]. Do not abuse sched_clock() for such things.

	Ingo

  reply	other threads:[~2007-07-19 14:51 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-17 11:44 [patch] softlockup watchdog: fix Xen bogosity Ingo Molnar
2007-07-17 14:17 ` Jeremy Fitzhardinge
2007-07-17 15:49   ` [patch] fix the softlockup watchdog to actually work Ingo Molnar
2007-07-17 17:03     ` Randy Dunlap
2007-07-17 17:25       ` Ingo Molnar
2007-07-17 18:14       ` Linus Torvalds
2007-07-17 21:38         ` Randy Dunlap
2007-07-19  7:22     ` Andrew Morton
2007-07-19  7:46       ` Ingo Molnar
2007-07-19  7:51       ` Ingo Molnar
2007-07-19 14:31         ` Jeremy Fitzhardinge
2007-07-19 14:35           ` Ingo Molnar
2007-07-19 14:40             ` Jeremy Fitzhardinge
2007-07-19 14:46             ` Jeremy Fitzhardinge
2007-07-19 14:50               ` Ingo Molnar [this message]
2007-07-19 15:04                 ` Jeremy Fitzhardinge
2007-07-19 15:09                   ` Ingo Molnar
2007-07-19 15:21                     ` Jeremy Fitzhardinge
2007-07-19 15:42                       ` [patch] sched: implement cpu_clock(cpu) high-speed time source Ingo Molnar
2007-07-19 15:44                         ` [patch] sched: implement cpu_clock(cpu) high-speed time source, take #2 Ingo Molnar
2007-07-19 16:11                           ` Jeremy Fitzhardinge
2007-07-19 16:16                             ` Ingo Molnar
2007-07-19 16:18                               ` Jeremy Fitzhardinge
2007-07-19 16:21                                 ` Ingo Molnar
2007-07-19 16:29                                   ` Jeremy Fitzhardinge
2007-07-19 17:24                             ` Jens Axboe
2007-07-19 18:10                               ` Jeremy Fitzhardinge
2007-07-19 18:20                                 ` Jens Axboe
2007-07-25  8:49     ` [patch] fix the softlockup watchdog to actually work Andrew Morton
2007-07-25  8:52       ` Ingo Molnar
2007-07-25  8:55         ` Ingo Molnar
2007-07-25  9:00         ` Andrew Morton
2007-07-25  9:04           ` Ingo Molnar
2007-07-25  9:17             ` Andrew Morton
2007-07-25  9:23               ` Ingo Molnar
2007-07-25  9:59                 ` Jens Axboe
2007-07-25 11:04                   ` Ingo Molnar
2007-07-25 11:06                     ` Jens Axboe
2007-07-25 16:34       ` Andi Kleen
2007-10-03 23:49     ` Yinghai Lu

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