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

John Garry
2022-08-09T09:59:06Z

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.

>
>>
>>
>>
>>
>> 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.
>>
>>
>
>