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Message-ID: <1f498d4a-f93f-ceb4-b713-753196e5e08d@opensource.wdc.com>
Date:   Mon, 8 Aug 2022 07:52:17 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
 Gecko/20100101 Thunderbird/91.12.0
Subject: Re: [ata] 0568e61225: stress-ng.copy-file.ops_per_sec -15.0%
 regression
Content-Language: en-US
To:     kernel test robot <oliver.sang@intel.com>,
        John Garry <john.garry@huawei.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        linux-ide@vger.kernel.org, lkp@lists.01.org, lkp@intel.com,
        ying.huang@intel.com, feng.tang@intel.com,
        zhengjun.xing@linux.intel.com, fengwei.yin@intel.com
References: <YuzPMMnnY739Tnit@xsang-OptiPlex-9020>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <YuzPMMnnY739Tnit@xsang-OptiPlex-9020>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On 2022/08/05 1:05, kernel test robot wrote:
>=20
>=20
> Greeting,
>=20
> FYI, we noticed a -15.0% regression of stress-ng.copy-file.ops_per_sec =
due to commit:
>=20
>=20
> commit: 0568e6122574dcc1aded2979cd0245038efe22b6 ("ata: libata-scsi: ca=
p ata_device->max_sectors according to shost->max_sectors")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>=20
> in testcase: stress-ng
> on test machine: 96 threads 2 sockets Ice Lake with 256G memory
> with following parameters:
>=20
> 	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 def=
ault
max_sectors value, causing overhead due to more commands than necessary.

Will check what I see with my test rig.

>=20
>=20
>=20
>=20
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@intel.com>
>=20
>=20
> Details are as below:
> -----------------------------------------------------------------------=
--------------------------->
>=20
>=20
> To reproduce:
>=20
>         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 fil=
e for lkp run
>         sudo bin/lkp run generated-yaml-file
>=20
>         # if come across any failure that blocks the test,
>         # please remove ~/.lkp and /lkp dir to run from a clean state.
>=20
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> 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
>=20
> commit:=20
>   4cbfca5f77 ("scsi: scsi_transport_sas: cap shost opt_sectors accordin=
g to DMA optimal limit")
>   0568e61225 ("ata: libata-scsi: cap ata_device->max_sectors according =
to shost->max_sectors")
>=20
> 4cbfca5f7750520f 0568e6122574dcc1aded2979cd0=20
> ---------------- ---------------------------=20
>          %stddev     %change         %stddev
>              \          |                \ =20
>       1627           -14.9%       1385        stress-ng.copy-file.ops
>      27.01           -15.0%      22.96        stress-ng.copy-file.ops_p=
er_sec
>    8935079           -11.9%    7870629        stress-ng.time.file_syste=
m_outputs
>      14.88 =C2=B1  5%     -31.8%      10.14 =C2=B1  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 =C2=B1  9%      -0.1        0.17 =C2=B1 11%  mpstat.cpu.all.=
sys%
>       1.66 =C2=B1 37%      -1.2        0.51 =C2=B1 55%  perf-profile.ca=
lltrace.cycles-pp.f2fs_write_end.generic_perform_write.f2fs_buffered_writ=
e_iter.f2fs_file_write_iter.do_iter_readv_writev
>       1.66 =C2=B1 37%      -1.1        0.59 =C2=B1 25%  perf-profile.ch=
ildren.cycles-pp.f2fs_write_end
>       1.51 =C2=B1 40%      -1.1        0.45 =C2=B1 26%  perf-profile.ch=
ildren.cycles-pp.f2fs_dirty_data_folio
>       1.21 =C2=B1 49%      -1.0        0.23 =C2=B1 33%  perf-profile.ch=
ildren.cycles-pp.f2fs_update_dirty_folio
>       0.88 =C2=B1 56%      -0.8        0.04 =C2=B1111%  perf-profile.ch=
ildren.cycles-pp.native_queued_spin_lock_slowpath
>       0.14 =C2=B1 26%      +0.1        0.25 =C2=B1 28%  perf-profile.ch=
ildren.cycles-pp.page_cache_ra_unbounded
>       0.88 =C2=B1 56%      -0.8        0.04 =C2=B1112%  perf-profile.se=
lf.cycles-pp.native_queued_spin_lock_slowpath
>    3164876 =C2=B1  9%     -20.2%    2524713 =C2=B1  7%  perf-stat.i.cac=
he-misses
>  4.087e+08            -4.6%  3.899e+08        perf-stat.i.dTLB-loads
>     313050 =C2=B1 10%     -18.4%     255410 =C2=B1  6%  perf-stat.i.nod=
e-loads
>     972573 =C2=B1  9%     -16.4%     812873 =C2=B1  6%  perf-stat.i.nod=
e-stores
>    3114748 =C2=B1  9%     -20.2%    2484807 =C2=B1  7%  perf-stat.ps.ca=
che-misses
>  4.022e+08            -4.6%  3.837e+08        perf-stat.ps.dTLB-loads
>     308178 =C2=B1 10%     -18.4%     251418 =C2=B1  6%  perf-stat.ps.no=
de-loads
>     956996 =C2=B1  9%     -16.4%     799948 =C2=B1  6%  perf-stat.ps.no=
de-stores
>     358486            -8.3%     328694        proc-vmstat.nr_active_fil=
e
>    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 =C2=B1  2%  proc-vmstat.nr_inact=
ive_file
>     846362           -14.6%     722471        proc-vmstat.nr_written
>     358486            -8.3%     328694        proc-vmstat.nr_zone_activ=
e_file
>     100181            +9.9%     110078 =C2=B1  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
>=20
>=20
>=20
>=20
> Disclaimer:
> Results have been estimated based on internal Intel analysis and are pr=
ovided
> for informational purposes only. Any difference in system hardware or s=
oftware
> design or configuration may affect actual performance.
>=20
>=20


--=20
Damien Le Moal
Western Digital Research