From: Nick Piggin <npiggin@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>,
akpm@linux-foundation.org, mm-commits@vger.kernel.org,
drepper@redhat.com, oleg@tv-sign.ru, sebastien.dugue@bull.net,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch] change futex_wait() to hrtimers
Date: Mon, 12 Mar 2007 10:16:28 +0100 [thread overview]
Message-ID: <20070312091628.GE28546@wotan.suse.de> (raw)
In-Reply-To: <20070312091006.GF21024@elte.hu>
On Mon, Mar 12, 2007 at 10:10:06AM +0100, Ingo Molnar wrote:
>
> * Roland McGrath <roland@redhat.com> wrote:
>
> > I agree it should restart. But I don't think this is quite right in
> > the timeout case. It will increase the total maximum real time spent
> > arbitrarily by the amount of time elapsed in signal handlers. Other
> > restartable, timed calls have to convert to an absolute timeout for
> > the restart block (and convert back when doing the restart).
>
> i dont think we should try to do this. We should not and cannot do
> anything about all of the artifacts that comes with the use of relative
> timeouts and schedule_timeout().
>
> basically, using jiffies here (which schedule_timeout() does) is
> /fundamentally/ imprecise. If you get many interrupts, rounding errors
> sum up - and there's nothing we can do about it!
Well I did convert futex_wait to an absolute timeout based version in
the subsequent incremental patch. I think that is OK?
next prev parent reply other threads:[~2007-03-12 9:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200703110814.l2B8EaI1007615@shell0.pdx.osdl.net>
[not found] ` <20070312011259.3834A1801C4@magilla.sf.frob.com>
2007-03-12 9:10 ` [patch] change futex_wait() to hrtimers Ingo Molnar
2007-03-12 9:16 ` Nick Piggin [this message]
2007-03-12 11:02 ` Ingo Molnar
2007-03-12 11:13 ` Nick Piggin
2007-03-12 11:19 ` Ingo Molnar
2007-03-12 11:29 ` Nick Piggin
2007-03-12 11:38 ` Ingo Molnar
2007-03-12 11:52 ` Nick Piggin
2007-03-12 12:21 ` Ingo Molnar
2007-03-12 12:36 ` Nick Piggin
2007-03-12 11:19 ` Thomas Gleixner
2007-03-12 11:27 ` Andi Kleen
2007-03-12 11:00 ` Thomas Gleixner
2007-03-12 10:58 ` Andi Kleen
2007-03-12 11:04 ` Ingo Molnar
2007-03-12 11:20 ` Andi Kleen
2007-03-12 11:28 ` Ingo Molnar
2007-03-12 14:12 ` Theodore Tso
2007-03-12 14:22 ` Andi Kleen
2007-03-12 14:31 ` Ingo Molnar
2007-03-12 14:32 ` Nick Piggin
2007-03-15 0:03 linux
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