From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: alan@redhat.com
Subject: Re: [Qemu-devel] Re: [RFC][PATCH] make sure disk writes actually hit disk
Date: Fri, 28 Jul 2006 21:30:09 +0100 [thread overview]
Message-ID: <200607282130.11255.paul@codesourcery.com> (raw)
In-Reply-To: <44CA7102.1020402@redhat.com>
> > With a proper async API, is there any reason why we would want this to be
> > tunable? I don't think there's much of a benefit of prematurely claiming
> > a write is complete especially once the SCSI emulation can support
> > multiple simultaneous requests.
>
> You're right. This O_SYNC bandaid should probably stay in place
> to prevent data corruption, until the AIO framework is ready to
> be used.
It's arguable whether O_SYNC is needed at all. Qemu doesn't claim data is
written to disk, and provides facilities for the guest OS to flush the cache,
just like real hardware does.
Have you measured the impact of O_SYNC? I wouldn't be surprised if it was
significant.
Paul
next prev parent reply other threads:[~2006-07-28 20:30 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-28 19:54 [Qemu-devel] [RFC][PATCH] make sure disk writes actually hit disk Rik van Riel
2006-07-28 19:58 ` [Qemu-devel] " Rik van Riel
2006-07-28 20:12 ` Anthony Liguori
2006-07-28 20:18 ` Rik van Riel
2006-07-28 20:30 ` Paul Brook [this message]
2006-07-28 20:43 ` Rik van Riel
2006-07-28 21:01 ` Paul Brook
2006-07-31 7:08 ` Jens Axboe
2006-07-29 9:57 ` [Qemu-devel] " Fabrice Bellard
2006-07-29 14:59 ` Rik van Riel
2006-07-29 16:04 ` Paul Brook
2006-07-29 16:22 ` Rik van Riel
2006-07-29 16:31 ` Paul Brook
2006-07-31 7:08 ` Jens Axboe
2006-07-29 17:33 ` Bill C. Riemers
2006-07-30 21:47 ` Jamie Lokier
2006-07-30 21:41 ` Jamie Lokier
2006-07-31 9:52 ` andrzej zaborowski
2006-07-31 10:17 ` Jens Axboe
2006-07-31 17:50 ` andrzej zaborowski
2006-07-31 7:08 ` Jens Axboe
2006-07-31 7:56 ` Jonas Maebe
2006-07-31 8:18 ` Jens Axboe
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