From: William Lee Irwin III <wli@holomorphy.com>
To: Joel Becker <jlbec@evilplan.org>
Cc: Avi Kivity <avi@exanet.com>, Yasushi Saito <ysaito@hpl.hp.com>,
linux-aio@kvack.org, linux-kernel@vger.kernel.org,
suparna@in.ibm.com, Janet Morgan <janetmor@us.ibm.com>
Subject: Re: [PATCH 1/2] aio: add vectored I/O support
Date: Sat, 16 Oct 2004 05:05:04 -0700 [thread overview]
Message-ID: <20041016120504.GV5607@holomorphy.com> (raw)
In-Reply-To: <20041016053721.GD17142@parcelfarce.linux.theplanet.co.uk>
On Sat, Oct 16, 2004 at 07:18:45AM +0200, Avi Kivity wrote:
>> It is a huge performance win, at least on the 2.4-based RHEL kernel.
>> Large reads (~256K) using 4K iocbs are very slow on a large RAID, while
>> after I coded a similar patch I got a substantial speedup.
On Sat, Oct 16, 2004 at 06:37:21AM +0100, Joel Becker wrote:
> I'd think we should fix the submission path instead. Why create
> iovs _and_ iocbs when we only need to create one? And even if we
> decided aio_readv() was still nice to keep, we'd want to fix this
> inefficiency in io_submit().
Disk I/O can vector across iocb's; however, network I/O requires
temporal ordering not imposed by sequential iocb submission, barring
unusual extensions to the semantics.
-- wli
prev parent reply other threads:[~2004-10-16 12:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-14 20:10 [PATCH 1/2] aio: add vectored I/O support Yasushi Saito
2004-10-16 3:13 ` Joel Becker
2004-10-16 5:18 ` Avi Kivity
2004-10-16 5:37 ` Joel Becker
2004-10-16 8:43 ` Avi Kivity
2004-10-16 16:28 ` Joel Becker
2004-10-16 17:29 ` Avi Kivity
2004-10-17 0:14 ` Joel Becker
2004-10-17 6:25 ` Avi Kivity
2004-10-16 12:05 ` William Lee Irwin III [this message]
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