From: Andrea Arcangeli <aarcange@redhat.com>
To: Jens Axboe <qemu@kernel.dk>
Cc: qemu-devel@nongnu.org, Gerd Hoffmann <kraxel@redhat.com>,
kvm-devel <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [RFC] Replace posix-aio with custom thread pool
Date: Fri, 12 Dec 2008 12:51:33 +0100 [thread overview]
Message-ID: <20081212115133.GI6809@random.random> (raw)
In-Reply-To: <20081212082309.GI23742@kernel.dk>
On Fri, Dec 12, 2008 at 09:23:10AM +0100, Jens Axboe wrote:
> aio is only async with O_DIRECT, with buffered IO it's sync.
That's very bad, because aio is as needed for O_DIRECT as for buffered
read seeking workloads that otherwise have zero chance to fill the
I/O pipe... (well unless one is threading in userland which is obviously
less efficient than what aio could achieve in kernel space, even
without taking cfq screwed bucketing into account).
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Jens Axboe <qemu@kernel.dk>
Cc: qemu-devel@nongnu.org, kvm-devel <kvm@vger.kernel.org>,
Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [Qemu-devel] [RFC] Replace posix-aio with custom thread pool
Date: Fri, 12 Dec 2008 12:51:33 +0100 [thread overview]
Message-ID: <20081212115133.GI6809@random.random> (raw)
In-Reply-To: <20081212082309.GI23742@kernel.dk>
On Fri, Dec 12, 2008 at 09:23:10AM +0100, Jens Axboe wrote:
> aio is only async with O_DIRECT, with buffered IO it's sync.
That's very bad, because aio is as needed for O_DIRECT as for buffered
read seeking workloads that otherwise have zero chance to fill the
I/O pipe... (well unless one is threading in userland which is obviously
less efficient than what aio could achieve in kernel space, even
without taking cfq screwed bucketing into account).
next prev parent reply other threads:[~2008-12-12 11:51 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-05 21:21 [RFC] Replace posix-aio with custom thread pool Anthony Liguori
2008-12-05 21:21 ` [Qemu-devel] " Anthony Liguori
2008-12-06 9:03 ` Blue Swirl
2008-12-06 18:26 ` Jamie Lokier
2008-12-08 18:23 ` Anthony Liguori
2008-12-08 18:23 ` Anthony Liguori
2008-12-09 15:51 ` Gerd Hoffmann
2008-12-09 16:01 ` Anthony Liguori
2008-12-10 16:44 ` Andrea Arcangeli
2008-12-10 17:21 ` Anthony Liguori
2008-12-10 17:21 ` Anthony Liguori
2008-12-10 17:29 ` Gerd Hoffmann
2008-12-10 18:50 ` Anthony Liguori
2008-12-10 19:08 ` Andrea Arcangeli
2008-12-10 19:08 ` Andrea Arcangeli
2008-12-11 13:12 ` Andrea Arcangeli
2008-12-11 15:24 ` Gerd Hoffmann
2008-12-11 15:24 ` Gerd Hoffmann
2008-12-11 15:53 ` Andrea Arcangeli
2008-12-11 15:53 ` Andrea Arcangeli
2008-12-11 16:11 ` Gerd Hoffmann
2008-12-11 16:11 ` Gerd Hoffmann
2008-12-11 16:49 ` Andrea Arcangeli
2008-12-11 16:49 ` Andrea Arcangeli
2008-12-11 17:20 ` Gerd Hoffmann
2008-12-11 17:20 ` Gerd Hoffmann
2008-12-11 18:11 ` Andrea Arcangeli
2008-12-11 18:11 ` Andrea Arcangeli
2008-12-11 20:38 ` Gerd Hoffmann
2008-12-11 20:38 ` Gerd Hoffmann
2008-12-11 20:40 ` Anthony Liguori
2008-12-12 8:23 ` Jens Axboe
2008-12-12 8:23 ` Jens Axboe
2008-12-12 11:51 ` Andrea Arcangeli [this message]
2008-12-12 11:51 ` Andrea Arcangeli
2008-12-12 11:54 ` Jens Axboe
2008-12-12 11:54 ` Jens Axboe
2008-12-12 14:13 ` Andrea Arcangeli
2008-12-12 14:13 ` Andrea Arcangeli
2008-12-12 14:24 ` Anthony Liguori
2008-12-12 14:24 ` Anthony Liguori
2008-12-12 16:33 ` Chris Wright
2008-12-12 16:33 ` Chris Wright
2008-12-12 16:51 ` Anthony Liguori
2008-12-12 16:51 ` Anthony Liguori
2008-12-12 16:52 ` Chris Wright
2008-12-12 16:52 ` Chris Wright
2008-12-11 21:32 ` Christoph Hellwig
2008-12-12 0:27 ` Andrea Arcangeli
2008-12-12 0:27 ` Andrea Arcangeli
2008-12-11 21:30 ` Christoph Hellwig
2008-12-11 16:41 ` Anthony Liguori
2008-12-11 16:41 ` Anthony Liguori
2008-12-12 14:24 ` Andrea Arcangeli
2008-12-12 14:24 ` Andrea Arcangeli
2008-12-12 14:35 ` Anthony Liguori
2008-12-12 14:35 ` Anthony Liguori
2008-12-12 15:44 ` Andrea Arcangeli
2008-12-12 15:44 ` Andrea Arcangeli
2008-12-12 16:49 ` Anthony Liguori
2008-12-12 16:49 ` Anthony Liguori
2008-12-12 17:09 ` Andrea Arcangeli
2008-12-12 17:09 ` Andrea Arcangeli
2008-12-12 17:25 ` Anthony Liguori
2008-12-12 17:25 ` Anthony Liguori
2008-12-12 17:52 ` Andrea Arcangeli
2008-12-12 17:52 ` Andrea Arcangeli
2008-12-12 18:17 ` Anthony Liguori
2008-12-12 18:17 ` Anthony Liguori
2008-12-12 18:26 ` Andrea Arcangeli
2008-12-12 20:12 ` Gerd Hoffmann
2008-12-12 20:17 ` Anthony Liguori
2008-12-12 20:35 ` Gerd Hoffmann
2008-12-09 17:16 ` Avi Kivity
2008-12-17 14:44 ` Ian Jackson
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