From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <ak@muc.de>
Cc: linux-kernel@vger.kernel.org, Lee Revell <rlrevell@joe-job.com>
Subject: Re: [patch] remove the BKL (Big Kernel Lock), this time for real
Date: Wed, 15 Sep 2004 17:58:36 +0200 [thread overview]
Message-ID: <20040915155836.GA11925@elte.hu> (raw)
In-Reply-To: <m3vfefa61l.fsf@averell.firstfloor.org>
* Andi Kleen <ak@muc.de> wrote:
> Ingo Molnar <mingo@elte.hu> writes:
>
> > the attached patch is a new approach to get rid of Linux's Big Kernel
> > Lock as we know it today.
>
> Interesting approach. Did you measure what it does to context switch
> rates? Usually adding semaphores tends to increase them a lot.
not yet - i've coded it up today. Perhaps the lowlatency audio folks
(who are most interested in BKL-latency removal) could report some
numbers?
but as i've replied to Linus too, i believe that _if_ the context-switch
rate goes up then some piece of code uses the BKL way too often! So
having a semaphore here might in fact help fixing those rare cases.
> One minor comment only:
> Please CSE "current" manually. It generates much better code
> on some architectures because the compiler cannot do it for you.
yeah, agreed, will do.
Ingo
next prev parent reply other threads:[~2004-09-15 16:00 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <2EJTp-7bx-1@gated-at.bofh.it>
2004-09-15 15:46 ` [patch] remove the BKL (Big Kernel Lock), this time for real Andi Kleen
2004-09-15 15:58 ` Ingo Molnar [this message]
2004-09-15 20:11 ` Ingo Molnar
2004-09-16 1:17 ` Nick Piggin
2004-09-16 14:28 ` Bill Davidsen
2004-09-16 22:29 ` Bill Huey
2004-09-16 22:40 ` David S. Miller
2004-09-16 22:51 ` Bill Huey
2004-09-16 22:54 ` David S. Miller
2004-09-16 23:01 ` Bill Huey
2004-09-16 23:33 ` William Lee Irwin III
2004-09-17 6:43 ` Ingo Molnar
2004-09-17 7:21 ` Tony Lee
2004-09-18 5:44 Manfred Spraul
2004-09-18 13:09 ` Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2004-09-15 15:18 Ingo Molnar
2004-09-15 15:40 ` Linus Torvalds
2004-09-15 15:55 ` Ingo Molnar
2004-09-15 17:04 ` Ricky Beam
2004-09-15 19:39 ` Ingo Molnar
2004-09-15 18:28 ` Chris Wedgwood
2004-09-15 21:25 ` William Lee Irwin III
2004-09-17 10:39 ` Ingo Molnar
2004-09-17 12:53 ` Ingo Molnar
2004-09-17 20:56 ` Andrea Arcangeli
2004-09-18 8:02 ` Ingo Molnar
2004-09-18 23:36 ` Andrea Arcangeli
2004-09-17 13:26 ` Andrea Arcangeli
2004-09-17 13:47 ` William Lee Irwin III
2004-09-17 13:56 ` Andrea Arcangeli
2004-09-17 14:18 ` William Lee Irwin III
2004-09-17 15:16 ` Linus Torvalds
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