On Tue, Feb 02, 2021 at 04:18:27PM +0800, Xing, Zhengjun wrote:

On 1/14/2021 11:18 AM, Roman Gushchin wrote:

On Thu, Jan 14, 2021 at 10:51:51AM +0800, kernel test robot wrote:

Greeting,

FYI, we noticed a -62.4% regression of hackbench.throughput due to commit:

Hi!

Commit "mm: memcg/slab: optimize objcg stock draining" (currently only in the mm tree,
so no stable hash) should improve the hackbench regression.

The commit has been merged into Linux mainline :
 3de7d4f25a7438f09fef4e71ef111f1805cd8e7c ("mm: memcg/slab: optimize objcg
stock draining")
I test the regression still existed.

Hm, so in your setup it's about the same with and without this commit?

It's strange because I've received a letter stating a 45.2% improvement recently:
https://lkml.org/lkml/2021/1/27/83

They are different test cases, 45.2% improvement test case run in "thread" mode, -62.4% regression test case run in "process" mode.
From 286e04b8ed7a0427 to 3de7d4f25a7438f09fef4e71ef1 there are two regressions for process mode :
1) 286e04b8ed7a0427 to 10befea91b61c4e2c2d1df06a2e  (-62.4% regression)
2) 10befea91b61c4e2c2d1df06a2e to d3921cb8be29ce5668c64e23ffd (-22.3% regression)

3de7d4f25a7438f09fef4e71ef111f1805cd8e7c only fix the regression 2) , so the value of "hackbench.throughput" for 3de7d4f25a7438f09fef4e71ef1(71824) and 10befea91b61c4e2c2d1df06a2e (72220) is very closed.

Regression 1) still existed. 

=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/nr_threads/iterations/mode/ipc/cpufreq_governor/ucode:
  lkp-csl-2sp7/hackbench/debian-10.4-x86_64-20200603.cgz/x86_64-rhel-8.3/gcc-9/100%/4/process/socket/performance/0x5003003

commit:
  286e04b8ed7a04279ae277f0f024430246ea5eec
  10befea91b61c4e2c2d1df06a2e978d182fcf792
  d3921cb8be29ce5668c64e23ffdaeec5f8c69399
  3de7d4f25a7438f09fef4e71ef111f1805cd8e7c
  v5.11-rc6

286e04b8ed7a0427 10befea91b61c4e2c2d1df06a2e d3921cb8be29ce5668c64e23ffd 3de7d4f25a7438f09fef4e71ef1                   v5.11-rc6
---------------- --------------------------- --------------------------- --------------------------- ---------------------------
         %stddev     %change         %stddev     %change         %stddev     %change         %stddev     %change         %stddev
             \          |                \          |                \          |                \          |                \
    192087 ±  8%     -62.4%      72220 ± 16%     -70.8%      56091 ±  3%     -62.6%      71824 ±  2%     -62.4%      72250 ±  2%  hackbench.throughput

Thanks!
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-- 
Zhengjun Xing