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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.


  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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