On 1/31/24 11:17 AM, Bart Van Assche wrote:
> On 1/31/24 07:42, kernel test robot wrote:
>> kernel test robot noticed a -72.9% regression of fio.write_iops on:
>>
>>
>> commit: 574e7779cf583171acb5bf6365047bb0941b387c ("block/mq-deadline: use separate insertion lists")
>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>>
>> testcase: fio-basic
>> test machine: 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G memory
>> parameters:
>>
>> runtime: 300s
>> disk: 1HDD
>> fs: xfs
>> nr_task: 100%
>> test_size: 128G
>> rw: write
>> bs: 4k
>> ioengine: io_uring
>> direct: direct
>> cpufreq_governor: performance
>
> The actual test is available in this file:
> https://download.01.org/0day-ci/archive/20240131/202401312320.a335db14-oliver.sang@xxxxxxxxx/repro-script
>
> I haven't found anything in that file for disabling merging. Merging
> requests decreases IOPS. Does this perhaps mean that this test is
> broken?
It's hard to know as nothing in this email or links include the actual
output of the job...
But if it's fio IOPS, then those are application side and don't
necessarily correlate to drive IOPS due to merging. Eg for fio iops, if
it does 4k sequential and we merge to 128k, then the fio perceived iops
will be 32 times larger than the device side.
I'll take a look, but seems like there might be something there. By
inserting into the other list, the request is also not available for
merging. And the test in question does single IOs at the time.
--
Jens Axboe
