Re: [PATCH 09/11] iotests/264: add mirror-cancel test-case

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

21.01.2021 04:26, Eric Blake wrote:
> On 11/18/20 12:04 PM, Vladimir Sementsov-Ogievskiy wrote:
>> Check that cancel doesn't wait for 10s of nbd reconnect timeout.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   tests/qemu-iotests/264     | 38 ++++++++++++++++++++++++++++++--------
>>   tests/qemu-iotests/264.out |  4 ++--
>>   2 files changed, 32 insertions(+), 10 deletions(-)
> 
>>   
>> +    def test_mirror_cancel(self):
>> +        # Mirror speed limit doesn't work well enough, it seems that mirror
>> +        # will run many parallel requests anyway. MAX_IN_FLIGHT is 16 and
>> +        # MAX_IO_BYTES is 1M in mirror.c, so let's use 20M disk.
>> +        self.init_vm(20 * 1024 * 1024)
>> +        self.start_job('blockdev-mirror')
> 
> Is this comment still accurate given recent work on the mirror filter?

Hmm, what do you mean? I missed it..

> I'm fine taking the patch as-is and tweaking it with followups, though,
> in order to make progress.

Good for me, of course

> 
>> +
>> +        result = self.vm.qmp('block-job-cancel', device='drive0')
>> +        self.assert_qmp(result, 'return', {})
>> +
>> +        start_t = time.time()
>> +        self.vm.event_wait('BLOCK_JOB_CANCELLED')
>> +        delta_t = time.time() - start_t
>> +        self.assertTrue(delta_t < 2.0)
> 
> I hope this doesn't fail on CI platforms under heavy load.  It didn't
> fail for me locally, but I hope we don't have to revisit it.  Is there
> any way we can test this in a manner that is not as fragile?

Hmm, I don't know. We want to check that cancel is not as long as reconnect timeout.. If it fails, we'll adjust the constants :) And we have no limit in it, we can use 1hour for reconnect-timeout and 10min for mirror to cancel for example (but probably something other may fail with such big timeouts)

> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> 


-- 
Best regards,
Vladimir