From: Rusty Russell <rusty@rustcorp.com.au>
To: Andi Kleen <ak@muc.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/6] lguest tsc fix
Date: Wed, 06 Jun 2007 10:25:49 +1000 [thread overview]
Message-ID: <1181089549.14054.77.camel@localhost.localdomain> (raw)
In-Reply-To: <20070605181510.GA7782@muc.de>
On Tue, 2007-06-05 at 20:15 +0200, Andi Kleen wrote:
> On Wed, Jun 06, 2007 at 12:56:36AM +1000, Rusty Russell wrote:
> > In recent -mm kernels, the TSC capability cannot be disabled,
> > resulting in a divide by zero error in the normal sched_clock.
>
> That will hopefully change. I hope hpa will just undo this.
>
> >
> > The correct fix is to have a special lguest sched_clock
> > implementation: this is as simple as it gets.
>
> But gettimeofday might still use it. Is that ok for you?
Yes, I don't think it will be any worse than before. Basically the
guest uses a dumb jiffies-based clock. The TSC patch later in this same
series changes it back to use the native sched_clock, and overrides
tsc_khz instead (based on information from the host).
Thanks,
Rusty.
prev parent reply other threads:[~2007-06-06 1:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-05 14:55 [PATCH 1/6] lguest example launcher fix Rusty Russell
2007-06-05 14:56 ` [PATCH 2/6] lguest tsc fix Rusty Russell
2007-06-05 14:58 ` [PATCH 3/6] lguest suppress IDE probing Rusty Russell
2007-06-05 15:00 ` [PATCH 4/6] lguest don't signal like crazy, use LHREQ_BREAK command Rusty Russell
2007-06-05 15:02 ` [PATCH 5/6] lguest use TSC Rusty Russell
2007-06-05 15:09 ` [PATCH 6/6] lguest use hrtimers Rusty Russell
2007-06-05 15:34 ` [PATCH 4/6] lguest don't signal like crazy, use LHREQ_BREAK command Matt Mackall
2007-06-06 0:07 ` Rusty Russell
2007-06-06 1:00 ` Matt Mackall
2007-06-05 15:32 ` [PATCH 3/6] lguest suppress IDE probing Matt Mackall
2007-06-05 16:07 ` Alan Cox
2007-06-05 16:10 ` Jeff Garzik
2007-06-05 17:09 ` James Morris
2007-06-06 1:10 ` Rusty Russell
2007-06-06 10:23 ` Alan Cox
2007-06-07 2:13 ` Rusty Russell
2007-06-07 14:45 ` Matt Mackall
2007-06-05 18:15 ` [PATCH 2/6] lguest tsc fix Andi Kleen
2007-06-06 0:25 ` Rusty Russell [this message]
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