From: Joel Becker <Joel.Becker@oracle.com>
To: Yury Polyanskiy <ypolyans@princeton.edu>
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 17:57:11 -0700 [thread overview]
Message-ID: <20100327005710.GA31009@mail.oracle.com> (raw)
In-Reply-To: <20100326180025.052d930f@penta.localdomain>
On Fri, Mar 26, 2010 at 06:00:25PM -0400, Yury Polyanskiy wrote:
> 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.
Yeah, I know. rdtsc hangcheck-timer really required no suspend
or cpufreq. Since it is only really used by servers, this wasn't a
terrible restriction. Then virtualization came along...
> > 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.
Makes sense. Andrew, would you mind pushing this through your
tree?
Acked-by: Joel Becker <joel.becker@oracle.com>
Joel
--
Dort wo man Bücher verbrennt, verbrennt man am Ende auch Mensch.
(Wherever they burn books, they will also end up burning people.)
- Heinrich Heine
Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127
next prev parent reply other threads:[~2010-03-27 0:58 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
2010-03-27 0:57 ` Joel Becker [this message]
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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