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From: Yury Polyanskiy <ypolyans@princeton.edu>
To: Joel Becker <Joel.Becker@oracle.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
	john stultz <johnstul@us.ibm.com>,
	Jan Glauber <jan.glauber@de.ibm.com>
Subject: Re: [PATCH] hangcheck-timer is broken on x86
Date: Fri, 26 Mar 2010 18:00:25 -0400	[thread overview]
Message-ID: <20100326180025.052d930f@penta.localdomain> (raw)
In-Reply-To: <20100326214648.GF9984@mail.oracle.com>

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On Fri, 26 Mar 2010 14:46:49 -0700
Joel Becker <Joel.Becker@oracle.com> wrote:

> On Tue, Mar 23, 2010 at 11:36:11PM -0400, Yury Polyanskiy wrote:

> 1) Does getrawmonotonic() satisfy hangcheck-timer?  What I mean is, will
> it always return the wallclock nanoseconds even in the face of CPU speed
> changes, suspend, udelay, or any other suspension of kernel operation?
> Yes, I know this is a tougher standard than rdtsc(), but this is what
> hangcheck-timer wants.  rdtsc() at least satisfied udelay and PCI hangs.

Yes, as far as I can tell. Note that rdtsc is hosed on suspend-resume.

> 
> 2) If it does satisfy, why not use it for all hangcheck usage instead of
> any ifdefs?

On my part, I didn't want to touch the S390 code since I can't test it.

Yury

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  reply	other threads:[~2010-03-26 22:01 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-24  3:36 [PATCH] hangcheck-timer is broken on x86 Yury Polyanskiy
2010-03-26 21:24 ` Andrew Morton
2010-03-26 21:52   ` Yury Polyanskiy
2010-03-26 21:46 ` Joel Becker
2010-03-26 22:00   ` Yury Polyanskiy [this message]
2010-03-27  0:57     ` Joel Becker
2010-03-27  2:02       ` Yury Polyanskiy
2010-03-27 22:03         ` Joel Becker
2010-03-27 22:51           ` Yury Polyanskiy
2010-03-27 23:36             ` Joel Becker
2010-03-28  2:08               ` Yury Polyanskiy
2010-03-29  1:00   ` john stultz
2010-03-29 14:11     ` Yury Polyanskiy
2010-03-29 16:43       ` john stultz
2010-03-29 17:04         ` Yury Polyanskiy
2010-03-29 18:44           ` john stultz
2010-03-29 19:53             ` Joel Becker
2010-03-29 21:08             ` Yury Polyanskiy
2010-03-29 21:43               ` john stultz
2010-03-29 22:34                 ` Yury Polyanskiy
2010-04-08  0:52                   ` Joel Becker

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