From: "Richard W.M. Jones" <rjones@redhat.com>
To: Peter Lieven <pl@kamp.de>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
libguestfs@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Effect of qemu-img convert -m and -W options
Date: Thu, 16 Nov 2017 15:12:33 +0000 [thread overview]
Message-ID: <20171116151233.GW2787@redhat.com> (raw)
In-Reply-To: <4ddf423b-a713-8f8b-e7dc-c970ad206885@kamp.de>
On Thu, Nov 16, 2017 at 03:51:29PM +0100, Peter Lieven wrote:
> Afaik all writes to the same QCOW2 serialize because of the s->lock that
> is held during the write. So its not suprising that there is no benefit from
> mutliple threads as long as reading from the RAW file involves no delay.
> Which is likely due to readahead of the OS.
I guess this would explain it, thanks.
Rich.
--
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next prev parent reply other threads:[~2017-11-16 15:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 11:52 [Qemu-devel] Effect of qemu-img convert -m and -W options Richard W.M. Jones
2017-11-16 14:47 ` Stefan Hajnoczi
2017-11-16 14:51 ` Peter Lieven
2017-11-16 15:12 ` Richard W.M. Jones [this message]
2017-11-16 17:20 ` Stefan Hajnoczi
2017-11-16 15:10 ` Richard W.M. Jones
2017-11-16 17:30 ` Stefan Hajnoczi
2017-11-16 18:00 ` Richard W.M. Jones
2017-11-20 15:57 ` Stefan Hajnoczi
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