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

From: Oliver Sang
Date: Fri Aug 12 2022 - 01:02:07 EST

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.

>
> >
> >>
> >>>
> >>>
> >>>
> >>>
> >>> If you fix the issue, kindly add following tag
> >>> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> >>>
> >>>
> >>> 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