On 12/08/2022 12:13, John Garry wrote:
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.
and since only 1HDD, the output of the following would be helpful:
/sys/block/sda/queue/max_sectors_kb
/sys/block/sda/queue/max_hw_sectors_kb
And for 5.19, if possible.
Thanks!
