From: Avi Kivity <avi@qumranet.com>
To: qemu-devel@nongnu.org
Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [kvm-devel] Re: [PATCH 1/3] Refactor AIO interface to allow other AIO implementations
Date: Tue, 22 Apr 2008 18:05:32 +0300 [thread overview]
Message-ID: <480DFEBC.1020504@qumranet.com> (raw)
In-Reply-To: <480DFBD9.4030802@codemonkey.ws>
Anthony Liguori wrote:
>>
>> If I submit sequential O_DIRECT reads with aio_read(), will they enter
>> the device read queue in the same order, and reach the disk in that
>> order (allowing for reordering when worthwhile by the elevator)?
>>
>
> There's no guarantee that any sort of order will be preserved by AIO
> requests. The same is true with writes. This is what fdsync is for,
> to guarantee ordering.
I believe he'd like a hint to get good scheduling, not a guarantee.
With a thread pool if the threads are scheduled out of order, so are
your requests. If the elevator doesn't plug the queue, the first few
requests may not be optimally sorted.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2008-04-22 15:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-17 19:26 [PATCH 1/3] Refactor AIO interface to allow other AIO implementations Anthony Liguori
2008-04-17 19:26 ` [PATCH 2/3] Split out posix-aio code Anthony Liguori
2008-04-17 19:26 ` [PATCH 3/3] Implement linux-aio backend Anthony Liguori
2008-04-18 15:09 ` Marcelo Tosatti
2008-04-18 15:18 ` Anthony Liguori
2008-04-18 17:46 ` Marcelo Tosatti
2008-04-17 19:38 ` [PATCH 1/3] Refactor AIO interface to allow other AIO implementations Daniel P. Berrange
2008-04-17 19:41 ` [kvm-devel] " Anthony Liguori
2008-04-17 20:00 ` Daniel P. Berrange
2008-04-17 20:05 ` Anthony Liguori
2008-04-18 12:43 ` Re: [kvm-devel] " Jamie Lokier
2008-04-18 15:23 ` Anthony Liguori
2008-04-18 16:22 ` [Qemu-devel] " Jamie Lokier
2008-04-18 16:32 ` Avi Kivity
2008-04-20 15:49 ` Jamie Lokier
2008-04-20 18:43 ` Avi Kivity
2008-04-20 23:39 ` Jamie Lokier
2008-04-21 6:39 ` Avi Kivity
2008-04-21 12:10 ` Jamie Lokier
2008-04-22 8:10 ` Avi Kivity
2008-04-22 14:28 ` [kvm-devel] " Jamie Lokier
2008-04-22 14:53 ` [Qemu-devel] " Anthony Liguori
2008-04-22 15:05 ` Avi Kivity [this message]
2008-04-22 15:23 ` [kvm-devel] " Jamie Lokier
2008-04-22 15:12 ` Jamie Lokier
2008-04-22 15:03 ` [Qemu-devel] " Avi Kivity
2008-04-22 15:36 ` [kvm-devel] " Jamie Lokier
2008-04-22 15:47 ` [Qemu-devel] " Javier Guerra
2008-04-21 0:31 ` Javier Guerra Giraldez
2008-04-21 6:41 ` Avi Kivity
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=480DFEBC.1020504@qumranet.com \
--to=avi@qumranet.com \
--cc=kvm-devel@lists.sourceforge.net \
--cc=mtosatti@redhat.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox