Re: [Qemu-devel] [PATCH] qcow2: avoid lseek on block_status if possible

[Vladimir Sementsov-Ogievskiy]

25.03.2019 17:56, Kevin Wolf wrote:
> 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.
> 

I found a framework which can print nice ASCII comparison tables for 
performance,
it's pip package named perf (https://pypi.org/project/perf/). But the problem 
with it,
that in RHEL there is rpm package which conflicts with this name: python-perf, 
which
do absolutely another thing.. So, to install pip install perf, you should first
yum remove python-perf..

-- 
Best regards,
Vladimir