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Re: [Qemu-devel] [PATCH] qcow2: avoid lseek on block_status if possible
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] qcow2: avoid lseek on block_status if possible |
Date: |
Mon, 25 Mar 2019 15:56:41 +0100 |
User-agent: |
Mutt/1.11.3 (2019-02-01) |
Am 25.01.2019 um 15:36 hat Vladimir Sementsov-Ogievskiy geschrieben:
> 25.01.2019 17:21, Vladimir Sementsov-Ogievskiy wrote:
> > Results on tmpfs:
> > cached is lseek cache by Kevin
> > detect is this patch
> > no lseek is just remove block_status query on bs->file->bs in
> > bdrv_co_block_status
> >
> > +---------------------+--------+--------+--------+----------+
> > | | master | cached | detect | no lseek |
> > +---------------------+--------+--------+--------+----------+
> > | test.qcow2 | 80 | 40 | 0.169 | 0.162 |
> > +---------------------+--------+--------+--------+----------+
> > | test_forward.qcow2 | 79 | 0.171 | 0.169 | 0.163 |
> > +---------------------+--------+--------+--------+----------+
> > | test_prealloc.qcow2 | 0.054 | 0.053 | 0.055 | 0.263 |
> > +---------------------+--------+--------+--------+----------+
>
> Forgot to say, tests by Kevin from branch
> https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg05463.html
>
> Hmm. Don't we have something like tests/qemu-iotests, but for performance?
> So, all these small pretty tests we have in mailing list may go as git
> patches?
Sounds like a good idea. Maybe we can just create a new subdirectory
qemu-iotests/perf/ and put some benchmark scripts there?
Of course, they wouldn't be able to tell PASS/FAIL like normal
qemu-iotests and so they wouldn't be integrated into the normal
qemu-iotests suite, but just return numbers that can be compared with
different setups or revisions on the same machine.
Kevin