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Date: Thu, 16 Nov 2017 18:00:54 +0000
From: "Richard W.M. Jones" <rjones@redhat.com>
Message-ID: <20171116180054.GZ2787@redhat.com>
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Subject: Re: [Qemu-devel] Effect of qemu-img convert -m and -W options
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: libguestfs@redhat.com, Peter Lieven <pl@kamp.de>, qemu-devel <qemu-devel@nongnu.org>

On Thu, Nov 16, 2017 at 05:30:48PM +0000, Stefan Hajnoczi wrote:
> On Thu, Nov 16, 2017 at 3:10 PM, Richard W.M. Jones <rjones@redhat.com> wrote:
> > Both local filesystems, but on different SATA devices.
> 
> Okay.  I'm curious what the strace -f output looks like (only the
> preadv(2)/pwritev(2) syscalls are interesting at the moment).

Here's the full strace from one run:

  http://oirase.annexia.org/tmp/strace.xz

The command is (with the output.qcow2 file created in a previous run):

  $ strace -o /tmp/strace -f -s 1024 qemu-img convert -f raw fedora-27.img -O qcow2 /var/tmp/output.qcow2 -m 8 -W -n

The version of qemu is: qemu-2.10.0-7.fc28.x86_64

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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