From: Peter Lieven <pl@kamp.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH 1.8 3/6] qemu-img: add option to specify alternate iobuffer size
Date: Mon, 25 Nov 2013 16:07:52 +0100 [thread overview]
Message-ID: <529367C8.7080301@kamp.de> (raw)
In-Reply-To: <529364B5.6000202@redhat.com>
On 25.11.2013 15:54, Paolo Bonzini wrote:
> Il 25/11/2013 14:57, Peter Lieven ha scritto:
>> since the convert process is basically a sync operation it might
>> be benificial in some case to change the hardcoded I/O buffer
>> size to an alternate (greater) value.
> Do you really need the extra knob? You can just add to BlockLimits the
> optimal transfer length, and use it unconditionally.
If you say patch 5 and 3 are ok. What could be done is to remove
this knob and increase the iobuf_size to cluster_size if cluster_size
is greater. I do not want to increase the default iobuf size to anything
greater than 2MB. I do not know why this was choosen, but maybe
there was a reason for it.
The storages we use here have a very strange page size of 15MB.
If I sent aligned 15MB chunks the performace is about +50% compared
to the original qemu-img.
Peter
next prev parent reply other threads:[~2013-11-25 15:07 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-25 13:57 [Qemu-devel] [PATCH 1.8 0/6] qemu-img convert optimizations Peter Lieven
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 1/6] qemu-img: add support for skipping zeroes in input during convert Peter Lieven
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 2/6] qemu-img: fix usage instruction for qemu-img convert Peter Lieven
2013-11-25 17:21 ` Eric Blake
2013-11-26 7:01 ` Peter Lieven
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 3/6] qemu-img: add option to specify alternate iobuffer size Peter Lieven
2013-11-25 14:54 ` Paolo Bonzini
2013-11-25 15:01 ` Peter Lieven
2013-11-25 15:07 ` Peter Lieven [this message]
2013-11-25 15:14 ` Paolo Bonzini
2013-11-25 15:24 ` Peter Lieven
2013-11-25 15:48 ` Paolo Bonzini
2013-11-25 15:56 ` Peter Lieven
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 4/6] block/iscsi: set bdi->cluster_size Peter Lieven
2013-11-25 14:51 ` Paolo Bonzini
2013-11-25 15:02 ` Paolo Bonzini
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 5/6] qemu-img: add option to align writes to cluster_sectors during convert Peter Lieven
2013-11-25 15:11 ` Paolo Bonzini
2013-11-25 15:32 ` Peter Lieven
2013-11-25 15:50 ` Paolo Bonzini
2013-11-25 15:55 ` Peter Lieven
2013-11-25 16:02 ` Paolo Bonzini
2013-11-25 16:11 ` Peter Lieven
2013-11-25 16:34 ` Paolo Bonzini
2013-11-25 13:57 ` [Qemu-devel] [PATCH 1.8 6/6] qemu-img: add option to show progress in sectors Peter Lieven
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