From: Christoph Hellwig <hch@lst.de>
To: qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>, kvm-devel <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [RFC] Replace posix-aio with custom thread pool
Date: Thu, 11 Dec 2008 22:30:55 +0100 [thread overview]
Message-ID: <20081211213055.GA2399@lst.de> (raw)
In-Reply-To: <20081211155335.GE14908@random.random>
On Thu, Dec 11, 2008 at 04:53:35PM +0100, Andrea Arcangeli wrote:
> > * It can't handle block allocation. Kernel handles that by doing
> > such writes synchronously via VFS layer (instead of the separate
> > aio code paths). Leads to horrible performance and bug reports
> > such as "installs on sparse files are very slow".
>
> I think here you mean O_DIRECT regardless of aio/sync API, I doubt aio
> has any relevance to block allocation in any way, so whatever problem
> we have with kernel API and O_DIRECT should also be there with
> sync-api + userland threads and O_DIRECT.
userland threads with O_DIRECT means only the thread doing block
allocation gets stalled, not any other.
next prev parent reply other threads:[~2008-12-11 21:31 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
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 [this message]
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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