Re: [ata] 0568e61225: stress-ng.copy-file.ops_per_sec -15.0% regression

John Garry
2022-08-12T11:13:31Z

On 12/08/2022 06:01, Oliver Sang wrote:
> hi, Damien Le Moal,
>
> On Tue, Aug 09, 2022 at 07:55:53AM -0700, Damien Le Moal wrote:
>> On 2022/08/09 2:58, John Garry wrote:
>>> On 08/08/2022 15:52, Damien Le Moal wrote:
>>>> On 2022/08/05 1:05, kernel test robot wrote:
>>>>>
>>>>>
>>>>> Greeting,
>>>>>
>>>>> FYI, we noticed a -15.0% regression of stress-ng.copy-file.ops_per_sec due to commit:
>>>>>
>>>>>
>>>>> commit: 0568e6122574dcc1aded2979cd0245038efe22b6 ("ata: libata-scsi: cap ata_device->max_sectors according to shost->max_sectors")
>>>>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>>>>>
>>>>> in testcase: stress-ng
>>>>> on test machine: 96 threads 2 sockets Ice Lake with 256G memory
>>>>> with following parameters:
>>>>>
>>>>> nr_threads: 10%
>>>>> disk: 1HDD
>>>>> testtime: 60s
>>>>> fs: f2fs
>>>>> class: filesystem
>>>>> test: copy-file
>>>>> cpufreq_governor: performance
>>>>> ucode: 0xb000280
>>>>
>>>> Without knowing what the device adapter is, hard to say where the problem is. I
>>>> suspect that with the patch applied, we may be ending up with a small default
>>>> max_sectors value, causing overhead due to more commands than necessary.
>>>>
>>>> Will check what I see with my test rig.
>>>
>>> As far as I can see, this patch should not make a difference unless the
>>> ATA shost driver is setting the max_sectors value unnecessarily low.
>>
>> That is my hunch too, hence my question about which host driver is being used
>> for this test... That is not apparent from the problem report.
>
> we noticed the commit is already in mainline now, and in our tests, there is
> still similar regression and also on other platforms.
> could you guide us how to check "which host driver is being used for this
> test"? hope to supply some useful information.
>

For me, a complete kernel log may help.

>>
>>>
>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> If you fix the issue, kindly add following tag
>>>>> Reported-by: kernel test robot <oliver.sang@intel.com>
>>>>>
>>>>>
>>>>> Details are as below:
>>>>> -------------------------------------------------------------------------------------------------->
>>>>>
>>>>>
>>>>> To reproduce:
>>>>>
>>>>> git clone https://github.com/intel/lkp-tests.git
>>>>> cd lkp-tests
>>>>> sudo bin/lkp install job.yaml # job file is attached in this email
>>>>> bin/lkp split-job --compatible job.yaml # generate the yaml file for lkp run
>>>>> sudo bin/lkp run generated-yaml-file
>>>>>
>>>>> # if come across any failure that blocks the test,
>>>>> # please remove ~/.lkp and /lkp dir to run from a clean state.
>>>>>
>>>>> =========================================================================================
>>>>> class/compiler/cpufreq_governor/disk/fs/kconfig/nr_threads/rootfs/tbox_group/test/testcase/testtime/ucode:
>>>>> filesystem/gcc-11/performance/1HDD/f2fs/x86_64-rhel-8.3/10%/debian-11.1-x86_64-20220510.cgz/lkp-icl-2sp1/copy-file/stress-ng/60s/0xb000280
>>>>>
>>>>> commit:
>>>>> 4cbfca5f77 ("scsi: scsi_transport_sas: cap shost opt_sectors according to DMA optimal limit")
>>>>> 0568e61225 ("ata: libata-scsi: cap ata_device->max_sectors according to shost->max_sectors")
>>>>>
>>>>> 4cbfca5f7750520f 0568e6122574dcc1aded2979cd0
>>>>> ---------------- ---------------------------
>>>>> %stddev %change %stddev
>>>>> \ | \
>>>>> 1627 -14.9% 1385 stress-ng.copy-file.ops
>>>>> 27.01 -15.0% 22.96 stress-ng.copy-file.ops_per_sec
>>>>> 8935079 -11.9% 7870629 stress-ng.time.file_system_outputs
>>>>> 14.88 ± 5% -31.8% 10.14 ± 3% stress-ng.time.percent_of_cpu_this_job_got
>>>>> 50912 -14.7% 43413 vmstat.io.bo
>>>>> 93.78 +1.4% 95.10 iostat.cpu.idle
>>>>> 3.89 -31.6% 2.66 iostat.cpu.iowait
>>>>> 4.01 -1.3 2.74 mpstat.cpu.all.iowait%
>>>>> 0.23 ± 9% -0.1 0.17 ± 11% mpstat.cpu.all.sys%
>>>>> 1.66 ± 37% -1.2 0.51 ± 55% perf-profile.calltrace.cycles-pp.f2fs_write_end.generic_perform_write.f2fs_buffered_write_iter.f2fs_file_write_iter.do_iter_readv_writev
>>>>> 1.66 ± 37% -1.1 0.59 ± 25% perf-profile.children.cycles-pp.f2fs_write_end
>>>>> 1.51 ± 40% -1.1 0.45 ± 26% perf-profile.children.cycles-pp.f2fs_dirty_data_folio
>>>>> 1.21 ± 49% -1.0 0.23 ± 33% perf-profile.children.cycles-pp.f2fs_update_dirty_folio
>>>>> 0.88 ± 56% -0.8 0.04 ±111% perf-profile.children.cycles-pp.native_queued_spin_lock_slowpath
>>>>> 0.14 ± 26% +0.1 0.25 ± 28% perf-profile.children.cycles-pp.page_cache_ra_unbounded
>>>>> 0.88 ± 56% -0.8 0.04 ±112% perf-profile.self.cycles-pp.native_queued_spin_lock_slowpath
>>>>> 3164876 ± 9% -20.2% 2524713 ± 7% perf-stat.i.cache-misses
>>>>> 4.087e+08 -4.6% 3.899e+08 perf-stat.i.dTLB-loads
>>>>> 313050 ± 10% -18.4% 255410 ± 6% perf-stat.i.node-loads
>>>>> 972573 ± 9% -16.4% 812873 ± 6% perf-stat.i.node-stores
>>>>> 3114748 ± 9% -20.2% 2484807 ± 7% perf-stat.ps.cache-misses
>>>>> 4.022e+08 -4.6% 3.837e+08 perf-stat.ps.dTLB-loads
>>>>> 308178 ± 10% -18.4% 251418 ± 6% perf-stat.ps.node-loads
>>>>> 956996 ± 9% -16.4% 799948 ± 6% perf-stat.ps.node-stores
>>>>> 358486 -8.3% 328694 proc-vmstat.nr_active_file
>>>>> 1121620 -11.9% 987816 proc-vmstat.nr_dirtied
>>>>> 179906 -6.7% 167912 proc-vmstat.nr_dirty
>>>>> 1151201 -1.7% 1131322 proc-vmstat.nr_file_pages
>>>>> 100181 +9.9% 110078 ± 2% proc-vmstat.nr_inactive_file
>>>>> 846362 -14.6% 722471 proc-vmstat.nr_written
>>>>> 358486 -8.3% 328694 proc-vmstat.nr_zone_active_file
>>>>> 100181 +9.9% 110078 ± 2% proc-vmstat.nr_zone_inactive_file
>>>>> 180668 -6.8% 168456 proc-vmstat.nr_zone_write_pending
>>>>> 556469 -3.5% 536985 proc-vmstat.pgactivate
>>>>> 3385454 -14.6% 2889953 proc-vmstat.pgpgout
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Disclaimer:
>>>>> Results have been estimated based on internal Intel analysis and are provided
>>>>> for informational purposes only. Any difference in system hardware or software
>>>>> design or configuration may affect actual performance.
>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> Damien Le Moal
>> Western Digital Research
> .