From: Jens Axboe <axboe@kernel.dk>
To: Bart Van Assche <bvanassche@acm.org>,
kernel test robot <oliver.sang@intel.com>
Cc: oe-lkp@lists.linux.dev, lkp@intel.com,
Linux Memory Management List <linux-mm@kvack.org>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
linux-block@vger.kernel.org, ying.huang@intel.com,
feng.tang@intel.com, fengwei.yin@intel.com
Subject: Re: [linux-next:master] [block/mq] 574e7779cf: fio.write_iops -72.9% regression
Date: Wed, 31 Jan 2024 11:42:46 -0700 [thread overview]
Message-ID: <9d2f99d8-ecd2-413e-b910-18e05239a2b8@kernel.dk> (raw)
In-Reply-To: <da4c78c1-a9d4-4a57-9765-2e6c35fa1062@acm.org>
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@intel.com/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
next prev parent reply other threads:[~2024-01-31 18:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-31 15:42 [linux-next:master] [block/mq] 574e7779cf: fio.write_iops -72.9% regression kernel test robot
2024-01-31 18:17 ` Bart Van Assche
2024-01-31 18:42 ` Jens Axboe [this message]
2024-02-01 7:18 ` Oliver Sang
2024-02-01 13:40 ` Jens Axboe
2024-02-01 14:03 ` Oliver Sang
2024-02-01 14:30 ` Jens Axboe
2024-02-01 14:45 ` Oliver Sang
2024-02-09 21:06 ` Jens Axboe
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