From: Lee Revell <rlrevell@joe-job.com>
To: Arjan van de Ven <arjanv@redhat.com>
Cc: Andrea Arcangeli <andrea@novell.com>,
Hugh Dickins <hugh@veritas.com>,
"Martin J. Bligh" <mbligh@aracnet.com>,
Andrea Arcangeli <andrea@suse.de>,
Alan Cox <alan@lxorguk.ukuu.org.uk>, Chris Wedgwood <cw@f00f.org>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option
Date: Sun, 12 Sep 2004 15:18:07 -0400 [thread overview]
Message-ID: <1095016687.1306.667.camel@krustophenia.net> (raw)
In-Reply-To: <20040910153421.GD24434@devserv.devel.redhat.com>
On Fri, 2004-09-10 at 11:34, Arjan van de Ven wrote:
> On Fri, Sep 10, 2004 at 05:28:52PM +0200, Andrea Arcangeli wrote:
> > On Fri, Sep 10, 2004 at 05:15:38PM +0200, Arjan van de Ven wrote:
> > > What we should consider regardless is disable the nesting of irqs for
> > > performance reasons but that's an independent matter
> >
> > disabling nesting completely sounds a bit too aggressive, but limiting
> > the nesting is probably a good idea.
>
> disabling is actually not a bad idea; hard irq handlers run for a very short
> time
The glaring exception is the IDE io completion, which can run for 2000+
usec even with a modern chipset and drive. Here's a 600 usec trace:
http://krustophenia.net/testresults.php?dataset=2.6.8-rc4-bk3-O7#/var/www/2.6.8-rc4-bk3-O7/ide_irq_latency_trace.txt
The timer, RTC, and soundcard interrupts (among others) will not like
being delayed this long. Ingo mentioned that this was not always done
in hardirq context; presumaby the I/O completion was done in a softirq
like SCSI. What was the motivation for moving such a long code path
into the hard irq handler?
Lee
next prev parent reply other threads:[~2004-09-12 19:18 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 [this message]
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
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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