From: Arjan van de Ven <arjanv@redhat.com>
To: Andrea Arcangeli <andrea@novell.com>
Cc: Jens Axboe <axboe@suse.de>, Lee Revell <rlrevell@joe-job.com>,
Ingo Molnar <mingo@elte.hu>, Chris Wedgwood <cw@f00f.org>,
Hugh Dickins <hugh@veritas.com>,
"Martin J. Bligh" <mbligh@aracnet.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option
Date: Mon, 13 Sep 2004 12:34:15 +0200 [thread overview]
Message-ID: <20040913103415.GA11567@devserv.devel.redhat.com> (raw)
In-Reply-To: <20040913103158.GA17625@dualathlon.random>
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On Mon, Sep 13, 2004 at 12:31:58PM +0200, Andrea Arcangeli wrote:
> On Mon, Sep 13, 2004 at 09:32:59AM +0200, Jens Axboe wrote:
> > completion from hardirq context, SCSI is the exception since it does it
> > defers the completion to softirq context.
>
> which btw doesn't really make much difference at all to run it in irq
> context with irq enabled since it'll run from irq context anyways and
> you'll still depend on nested hardirqs to avoid huge latencies from
> softirq handlers (the most difference between softirq and hardirq with
> irq enabled happens if you can use spin_lock_bh instead of spin_lock_irq
> in the critical sections to protect against other cpus).
and there is improved batching under really high (irq) load, esp when you
deal with stupid hw that can't give an irq for multiple packets or IO
requests at the same time (qlogic used to be like that until the driver got
fixed)
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next prev parent reply other threads:[~2004-09-13 10:34 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 23:25 [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option Chris Wedgwood
2004-09-09 23:55 ` Brian Gerst
2004-09-09 23:59 ` Chris Wedgwood
2004-09-10 6:40 ` Arjan van de Ven
2004-09-10 6:45 ` Chris Wedgwood
2004-09-10 6:52 ` Arjan van de Ven
2004-09-10 7:15 ` Chris Wedgwood
2004-09-10 7:21 ` Arjan van de Ven
2004-09-10 7:23 ` Chris Wedgwood
2004-09-10 7:35 ` Arjan van de Ven
2004-09-10 9:12 ` Alan Cox
2004-09-10 9:14 ` Alan Cox
2004-09-10 10:27 ` Russell King
2004-09-10 14:30 ` Martin J. Bligh
2004-09-10 15:06 ` Chris Wedgwood
2004-09-10 15:07 ` Hugh Dickins
2004-09-10 15:12 ` Alan Cox
2004-09-10 15:15 ` Arjan van de Ven
2004-09-10 15:28 ` Andrea Arcangeli
2004-09-10 15:09 ` Alan Cox
2004-09-10 15:34 ` Arjan van de Ven
2004-09-12 14:17 ` Andrea Arcangeli
2004-09-12 15:03 ` Martin J. Bligh
2004-09-12 15:45 ` Zwane Mwaikambo
2004-09-12 16:00 ` Martin J. Bligh
2004-10-20 16:27 ` Lee Revell
2004-10-21 15:18 ` Zwane Mwaikambo
2004-09-12 19:18 ` Lee Revell
2004-09-12 19:25 ` Chris Wedgwood
2004-09-12 19:35 ` Ingo Molnar
2004-09-12 19:40 ` Chris Wedgwood
2004-09-12 19:44 ` Ingo Molnar
2004-09-12 20:33 ` Andrea Arcangeli
2004-09-12 21:36 ` Lee Revell
2004-09-12 22:07 ` Andrea Arcangeli
2004-09-12 22:25 ` Lee Revell
2004-09-13 6:16 ` Ingo Molnar
2004-09-13 7:27 ` Lee Revell
2004-09-15 19:43 ` Bill Davidsen
2004-09-15 19:51 ` Andrea Arcangeli
2004-09-15 20:00 ` Ingo Molnar
2004-09-15 20:39 ` Lee Revell
2004-10-20 17:50 ` Timothy Miller
2004-09-13 7:32 ` Jens Axboe
2004-09-13 10:31 ` Andrea Arcangeli
2004-09-13 10:34 ` Arjan van de Ven [this message]
2004-09-13 12:30 ` Jens Axboe
2004-10-20 17:46 ` Timothy Miller
2004-09-13 10:51 ` Alan Cox
2004-09-13 20:26 ` Bill Davidsen
2004-09-14 5:20 ` Lee Revell
2004-10-20 15:46 ` Timothy Miller
2004-10-20 15:35 ` Arjan van de Ven
2004-10-20 16:39 ` Lee Revell
2004-10-20 16:50 ` Andrea Arcangeli
2004-10-20 16:55 ` Lee Revell
2004-10-20 17:08 ` Andrea Arcangeli
2004-10-20 17:15 ` Lee Revell
2004-10-20 17:34 ` Andrea Arcangeli
2004-10-20 17:58 ` Timothy Miller
2004-10-20 17:55 ` Lee Revell
2004-10-20 18:25 ` Timothy Miller
2004-10-20 18:28 ` Lee Revell
2004-10-20 18:51 ` Alan Cox
2004-10-20 23:19 ` Lee Revell
2004-09-10 15:16 ` Martin J. Bligh
2004-10-20 15:43 ` Timothy Miller
2004-10-20 15:35 ` Arjan van de Ven
2004-09-10 15:58 ` Alexander E. Patrakov
2004-09-10 16:19 ` Nathan Bryant
2004-09-10 17:54 ` Martin J. Bligh
2004-09-10 17:54 ` Bill Davidsen
2004-09-10 9:27 ` Alan Cox
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