From: Jens Axboe <qemu@kernel.dk>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [patch] non-blocking disk IO
Date: Tue, 4 Oct 2005 08:44:17 +0200 [thread overview]
Message-ID: <20051004064415.GF3511@suse.de> (raw)
In-Reply-To: <20051004052451.GJ4612@kalmia.hozed.org>
On Tue, Oct 04 2005, Troy Benjegerdes wrote:
> What we want is to be able to have the guest OS request some DMA
> I/O operation, and have qemu be able to use AIO so that the actual disk
> hardware can dump the data directly in the pages the userspace process
> on the guest OS ends up wanting it in, avoiding several expensive memcopy
> and context switch operations.
That should be easy enough to do already, with or without the
nonblocking patch. Just make sure to open the files O_DIRECT and align
the io buffers and lengths. With a 2.6 host, you can usually get away
with 512-b aligment, on 2.4 you may have to ensure 1k/4k alignment.
--
Jens Axboe
next prev parent reply other threads:[~2005-10-04 6:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-03 6:49 [Qemu-devel] [patch] non-blocking disk IO John Coiner
2005-10-03 7:09 ` Magnus Damm
2005-10-03 9:57 ` Elefterios Stamatogiannakis
2005-10-03 12:58 ` Christian MICHON
2005-10-04 7:17 ` John Coiner
2005-10-04 7:46 ` Christian MICHON
2005-10-04 8:52 ` Elefterios Stamatogiannakis
2005-10-04 9:35 ` Christian MICHON
2005-10-04 11:19 ` Christian MICHON
2005-10-04 12:22 ` Jens Axboe
2005-10-04 13:14 ` John Coiner
2005-10-04 13:20 ` Christian MICHON
2005-10-03 13:58 ` Jens Axboe
2005-10-03 22:29 ` John Coiner
2005-10-04 6:41 ` Jens Axboe
2005-10-04 1:35 ` Troy Benjegerdes
2005-10-04 3:25 ` John Coiner
2005-10-04 3:49 ` Henrik Nordstrom
2005-10-04 5:24 ` Troy Benjegerdes
2005-10-04 6:44 ` Jens Axboe [this message]
2005-10-03 18:33 ` Fabrice Bellard
2005-10-04 20:40 ` Brad Campbell
2005-10-04 23:03 ` John Coiner
2005-10-05 11:27 ` Brad Campbell
2005-10-05 14:28 ` Troy Benjegerdes
2005-11-28 22:41 ` Ryan Rempel
-- strict thread matches above, loose matches on Subject: below --
2005-10-03 12:41 John Coiner
2005-10-04 1:34 ` Troy Benjegerdes
2005-10-04 3:16 ` John Coiner
2005-10-04 14:26 ` Troy Benjegerdes
2005-10-04 22:11 ` John Coiner
2005-10-05 3:17 ` Troy Benjegerdes
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=20051004064415.GF3511@suse.de \
--to=qemu@kernel.dk \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.