From: William Lee Irwin III <wli@holomorphy.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ravikiran G Thirumalai <kiran@scalex86.org>
Subject: Re: [rfc][patch] queued spinlocks (i386)
Date: Fri, 23 Mar 2007 04:02:24 -0700 [thread overview]
Message-ID: <20070323110224.GP2986@holomorphy.com> (raw)
In-Reply-To: <20070323103243.GE11577@wotan.suse.de>
On Fri, Mar 23, 2007 at 11:04:18AM +0100, Ingo Molnar wrote:
>> isnt this patented by MS? (which might not worry you SuSE/Novell guys,
>> but it might be a worry for the rest of the world ;-)
On Fri, Mar 23, 2007 at 11:32:44AM +0100, Nick Piggin wrote:
> Hmm, it looks like they have implemented a system where the spinning
> cpu sleeps on a per-CPU variable rather than the lock itself, and
> the releasing cpu writes to that variable to wake it. They do this
> so that spinners don't continually perform exclusive->shared
> transitions on the lock cacheline. They call these things queued
> spinlocks. They don't seem to be very patent worthy either, but
> maybe it is what you're thinking of?
Those exclusive-to-shared transitions are among the cacheline transfers
typically accounted to the algorithms in their complexity analyses.
-- wli
next prev parent reply other threads:[~2007-03-23 11:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-23 8:59 [rfc][patch] queued spinlocks (i386) Nick Piggin
2007-03-23 9:40 ` Eric Dumazet
2007-03-23 9:59 ` Nick Piggin
2007-03-23 19:27 ` Ravikiran G Thirumalai
2007-03-23 10:04 ` Ingo Molnar
2007-03-23 10:10 ` Nick Piggin
2007-03-23 16:48 ` Parag Warudkar
2007-03-23 18:15 ` Davide Libenzi
2007-03-23 10:32 ` Nick Piggin
2007-03-23 10:40 ` Eric Dumazet
2007-03-23 11:02 ` William Lee Irwin III [this message]
2007-03-24 15:55 ` Nikita Danilov
2007-03-24 17:29 ` Ingo Molnar
2007-03-24 18:49 ` Nikita Danilov
2007-03-28 6:43 ` Nick Piggin
2007-03-28 19:26 ` Davide Libenzi
2007-03-28 22:00 ` Davide Libenzi
2007-03-29 1:36 ` Nick Piggin
2007-03-29 7:16 ` Nick Piggin
2007-03-30 0:27 ` Davide Libenzi
2007-03-30 1:59 ` Nick Piggin
2007-03-30 2:43 ` Davide Libenzi
2007-03-29 1:24 ` Nick Piggin
2007-03-24 21:41 ` Andrew Morton
2007-03-28 6:56 ` Nick Piggin
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