From: Christoph Hellwig <hch@infradead.org>
To: Jeremy Allison <jra@samba.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Daniel Ehrenberg <dehrenberg@google.com>,
Jens Axboe <axboe@kernel.dk>, Jeff Moyer <jmoyer@redhat.com>,
linux-kernel@vger.kernel.org, linux-aio@kvack.org
Subject: Re: Approaches to making io_submit not block
Date: Wed, 31 Aug 2011 01:34:29 -0400 [thread overview]
Message-ID: <20110831053429.GA13219@infradead.org> (raw)
In-Reply-To: <20110830230342.GB16326@samba2>
On Tue, Aug 30, 2011 at 04:03:42PM -0700, Jeremy Allison wrote:
> I have often wondered if this is actually the case ? I created
> my own glibc with a patches AIO that removed this restriction
> (thus had multiple outstanding threads on a single fd). In testing
> I saw a dramatic increase in performance (2x speedup) but then
> testing with use in actual code (Samba smbd) it made the client
> throughput *worse*. I never got to the bottom of this and so
> didn't submit my fixes to glibc.
>
> Any ideas if this is still the case ? Or comments on why glibc
> insists on only one outstanding request per fd ? Is this really
> needed for kernel performance ?
At least for writes you'll simply have multiple requests blocking on
i_mutex.
next prev parent reply other threads:[~2011-08-31 5:35 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-29 17:33 Approaches to making io_submit not block Daniel Ehrenberg
2011-08-30 5:32 ` Christoph Hellwig
2011-08-30 21:51 ` Daniel Ehrenberg
2011-08-31 5:26 ` Christoph Hellwig
2011-08-31 17:08 ` Andi Kleen
2011-08-31 21:00 ` Daniel Ehrenberg
2011-08-31 21:15 ` Andi Kleen
2011-09-01 4:18 ` Dave Chinner
2011-09-01 4:39 ` Andi Kleen
2011-09-01 6:54 ` Dave Chinner
2011-09-02 13:08 ` Ted Ts'o
2011-09-02 13:10 ` Christoph Hellwig
2011-09-01 3:39 ` Dave Chinner
2011-09-01 4:20 ` Christoph Hellwig
2011-08-30 7:02 ` Andi Kleen
[not found] ` <CAAK6Zt0Sh1GdEOb-tNf2FGXJs=e1Jbcqew13R_GdTqrv6vW97w@mail.gmail.com>
[not found] ` <x49k49uk2ox.fsf@segfault.boston.devel.redhat.com>
[not found] ` <4E5D5817.6040704@kernel.dk>
2011-08-30 22:19 ` Daniel Ehrenberg
2011-08-30 22:32 ` Jens Axboe
2011-08-30 22:41 ` Andrew Morton
2011-08-30 22:45 ` Daniel Ehrenberg
2011-08-30 22:54 ` Andrew Morton
2011-08-30 23:03 ` Jeremy Allison
2011-08-30 23:11 ` Andrew Morton
2011-08-31 11:04 ` Ulrich Drepper
2011-08-31 16:59 ` Jeremy Allison
2011-09-01 11:14 ` Ulrich Drepper
2011-09-01 15:58 ` Jeremy Allison
2011-09-01 16:04 ` Christoph Hellwig
2011-09-01 16:15 ` Jeremy Allison
2011-09-01 16:23 ` Christoph Hellwig
2011-09-01 16:31 ` Jeremy Allison
2011-09-01 16:34 ` Christoph Hellwig
2011-09-01 16:34 ` Jeremy Allison
2011-09-01 16:45 ` Christoph Hellwig
2011-09-01 16:57 ` Jeremy Allison
2011-08-31 5:34 ` Christoph Hellwig [this message]
2011-08-31 6:04 ` guy keren
2011-08-31 23:16 ` Daniel Ehrenberg
2011-08-31 23:48 ` guy keren
2011-08-31 23:59 ` Daniel Ehrenberg
2011-08-31 15:45 ` Gleb Natapov
2011-08-31 16:02 ` Avi Kivity
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