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

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

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.

> 
> 
> 
> 
> 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