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From: Max Reitz <mreitz@redhat.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	qemu-block@nongnu.org
Cc: kwolf@redhat.com, wencongyang2@huawei.com,
	xiechanglong.d@gmail.com, qemu-devel@nongnu.org,
	armbru@redhat.com, den@openvz.org, jsnow@redhat.com
Subject: Re: [PATCH v4 00/23] backup performance: block_status + async
Date: Wed, 20 Jan 2021 11:39:16 +0100
Message-ID: <29cccc86-a450-3326-2d70-f3022e32b5db@redhat.com> (raw)
In-Reply-To: <eb6ad5ca-0254-c9a7-63e3-3a4619e397cd@virtuozzo.com>

On 19.01.21 20:22, Vladimir Sementsov-Ogievskiy wrote:
> 19.01.2021 21:40, Max Reitz wrote:
>> On 16.01.21 22:46, Vladimir Sementsov-Ogievskiy wrote:
>>> Hi Max!
>>> I applied my series onto yours 129-fixing and found, that 129 fails 
>>> for backup.
>>> And setting small max-chunk and even max-workers to 1 doesn't help! 
>>> (setting
>>> speed like in v3 still helps).
>>>
>>> And I found, that the problem is that really, the whole backup job 
>>> goes during
>>> drain, because in new architecture we do just job_yield() during the 
>>> whole
>>> background block-copy.
>>>
>>> This leads to modifying the existing patch in the series, which does 
>>> job_enter()
>>> from job_user_pause: we just need call job_enter() from job_pause() 
>>> to cover
>>> not only user pauses but also drained_begin.
>>>
>>> So, now I don't need any additional fixing of 129.
>>>
>>> Changes in v4:
>>> - add a lot of Max's r-b's, thanks!
>>>
>>> 03: fix over-80 line (in comment), add r-b
>>> 09: was "[PATCH v3 10/25] job: call job_enter from job_user_pause",
>>>      now changed to finally fix 129 iotest, drop r-b
>>>
>>> 10: squash-in additional wording on max-chunk, fix error message, 
>>> keep r-b
>>> 17: drop extra include, assert job_is_cancelled() instead of check, 
>>> add r-b
>>> 18: adjust commit message, add r-b
>>> 23: add comments and assertion, about the fact that test doesn't support
>>>      paths with colon inside
>>>      fix s/disable-copy-range/use-copy-range/
>>
>> Hmmm, for me, 129 sometimes fails still, because it completes too 
>> quickly...  (The error then is that 'return[0]' does not exist in 
>> query-block-jobs’s result, because the job is already gone.)
>>
>> When I insert a print(result) after the query-block-jobs, I can see 
>> that the job has always progressed really far, even if its still 
>> running. (Like, generally the offset is just one MB shy of 1G.)
>>
>> I suspect the problem is that block-copy just copies too much from the 
>> start (by default); i.e., it starts 64 workers with, hm, well, 1 MB of 
>> chunk size?  Shouldn’t fill the 128 MB immediately...
>>
>> Anyway, limiting the number of workers (to 1) and the chunk size (to 
>> 64k) with x-perf does ensure that the backup job’s progress is limited 
>> to 1 MB or so, which looks fine to me.
>>
>> I suppose we should do that, then (in 129), before patch 17?
> 
> Yes, that sounds reasonable
> 
>>
>> (PS: I can also see a MacOS failure in iotest 256.  I suspect it’s 
>> related to this series, because 256 is a backup test (with iothreads), 
>> but I’m not sure yet.  The log is here:
>>
>> https://cirrus-ci.com/task/5276331753603072
>> )
>>
> 
> qemu received signal 31 ?
> 
> googling for MacOS...
> 
>   31    SIGUSR2      terminate process    User defined signal 2

coroutine-sigaltstack uses SIGUSR2 to set up new coroutines.  Perhaps 
it’s unrelated to backup?  Guess I’ll just run the test one more time. O:)

Max



  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-16 21:46 Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 01/23] qapi: backup: add perf.use-copy-range parameter Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 02/23] block/block-copy: More explicit call_state Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 03/23] block/block-copy: implement block_copy_async Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 04/23] block/block-copy: add max_chunk and max_workers parameters Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 05/23] block/block-copy: add list of all call-states Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 06/23] block/block-copy: add ratelimit to block-copy Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 07/23] block/block-copy: add block_copy_cancel Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 08/23] blockjob: add set_speed to BlockJobDriver Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 09/23] job: call job_enter from job_pause Vladimir Sementsov-Ogievskiy
2021-01-18 13:45   ` Max Reitz
2021-01-18 14:20     ` Max Reitz
2021-04-07 11:19   ` Max Reitz
2021-04-07 11:38     ` Vladimir Sementsov-Ogievskiy
2021-04-21  8:31       ` Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 10/23] qapi: backup: add max-chunk and max-workers to x-perf struct Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 11/23] iotests: 56: prepare for backup over block-copy Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 12/23] iotests: 185: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 13/23] iotests: 219: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 14/23] iotests: 257: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 15/23] block/block-copy: make progress_bytes_callback optional Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 16/23] block/backup: drop extra gotos from backup_run() Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 17/23] backup: move to block-copy Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 18/23] qapi: backup: disable copy_range by default Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 19/23] block/block-copy: drop unused block_copy_set_progress_callback() Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 20/23] block/block-copy: drop unused argument of block_copy() Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 21/23] simplebench/bench_block_job: use correct shebang line with python3 Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 22/23] simplebench: bench_block_job: add cmd_options argument Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 23/23] simplebench: add bench-backup.py Vladimir Sementsov-Ogievskiy
2021-01-18 14:01   ` Max Reitz
2021-01-18 15:07 ` [PATCH v4 00/23] backup performance: block_status + async Max Reitz
2021-01-18 17:04   ` Vladimir Sementsov-Ogievskiy
2021-01-19 18:40 ` Max Reitz
2021-01-19 19:22   ` Vladimir Sementsov-Ogievskiy
2021-01-19 19:29     ` Vladimir Sementsov-Ogievskiy
2021-01-20 10:39     ` Max Reitz [this message]
2021-01-20 13:50       ` Max Reitz
2021-01-20 14:34         ` Max Reitz
2021-01-20 14:44           ` Max Reitz
2021-01-20 15:53             ` Max Reitz
2021-01-20 16:00               ` Max Reitz
2021-01-20 16:04               ` Daniel P. Berrangé
2021-01-20 16:40                 ` Max Reitz
2021-01-20 10:20 ` [PATCH v4 11.5/23] iotests/129: Limit backup's max-chunk/max-workers Max Reitz
2021-01-20 11:24   ` Vladimir Sementsov-Ogievskiy

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