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From: Thomas Gleixner <tglx@linutronix.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <npiggin@suse.de>, 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
Subject: Re: [patch] change futex_wait() to hrtimers
Date: Mon, 12 Mar 2007 12:19:45 +0100	[thread overview]
Message-ID: <1173698386.13341.87.camel@localhost.localdomain> (raw)
In-Reply-To: <20070312110204.GD2231@elte.hu>

On Mon, 2007-03-12 at 12:02 +0100, Ingo Molnar wrote:
> > Well I did convert futex_wait to an absolute timeout based version in 
> > the subsequent incremental patch. I think that is OK?
> 
> it still has the rounding artifacts: using timer_list there is no way to 
> do a precise long sleep based on many small sleeps.
> 
> even if this means more work for you (i'm sorry about that!) i'm quite 
> sure we should take Sebastien's hrtimers based implementation of 
> futex_wait(), and use the nanosleep method to restart it. There's no 
> point in further tweaking the imprecise approach: whenever some timeout 
> needs to be restarted, it's a candidate for hrtimers.
> 
> until then, glibc already handles timeouts and restarts it manually.

This also allows us to add a seperate absolute time bases futex op,
which allows to remove the conversion of abstime to reltime in glibc.

	tglx



  parent reply	other threads:[~2007-03-12 11:13 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
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 [this message]
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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