On Wed 04-11-20 09:20:04, Xing Zhengjun wrote: > > > On 11/2/2020 6:02 PM, Michal Hocko wrote: > > On Mon 02-11-20 17:53:14, Rong Chen wrote: > > > > > > > > > On 11/2/20 5:27 PM, Michal Hocko wrote: > > > > On Mon 02-11-20 17:15:43, kernel test robot wrote: > > > > > Greeting, > > > > > > > > > > FYI, we noticed a -22.7% regression of will-it-scale.per_process_ops > > > > > due to commit: > > > > > > > > > > > > > > > commit: bd0b230fe14554bfffbae54e19038716f96f5a41 ("mm/memcg: unify > > > > > swap and memsw page counters") > > > > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > > > I really fail to see how this can be anything else than a data structure > > > > layout change. There is one counter less. > > > > > > > > btw. are cgroups configured at all? What would be the configuration? > > > > > > Hi Michal, > > > > > > We used the default configure of cgroups, not sure what configuration you > > > want, > > > could you give me more details? and here is the cgroup info of > > > will-it-scale > > > process: > > > > > > $ cat /proc/3042/cgroup > > > 12:hugetlb:/ > > > 11:memory:/system.slice/lkp-bootstrap.service > > > > OK, this means that memory controler is enabled and in use. Btw. do you > > get the original performance if you add one phony page_counter after the > > union? > > > I add one phony page_counter after the union and re-test, the regression > reduced to -1.2%. It looks like the regression caused by the data structure > layout change.
Thanks for double checking. Could you try to cache align the page_counter struct? If that helps then we should figure which counters acks against each other by adding the alignement between the respective counters. > ========================================================================================= > tbox_group/testcase/rootfs/kconfig/compiler/nr_task/mode/test/cpufreq_governor/ucode/debug-setup: > > lkp-hsw-4ex1/will-it-scale/debian-10.4-x86_64-20200603.cgz/x86_64-rhel-8.3/gcc-9/50%/process/page_fault2/performance/0x16/test1 > > commit: > 8d387a5f172f26ff8c76096d5876b881dec6b7ce > bd0b230fe14554bfffbae54e19038716f96f5a41 > b3233916ab0a883e1117397e28b723bd0e4ac1eb (debug patch add one phony > page_counter after the union) > > 8d387a5f172f26ff bd0b230fe14554bfffbae54e190 b3233916ab0a883e1117397e28b > ---------------- --------------------------- --------------------------- > %stddev %change %stddev %change %stddev > \ | \ | \ > 187632 -22.8% 144931 -1.2% 185391 > will-it-scale.per_process_ops > 13509525 -22.8% 10435073 -1.2% 13348181 > will-it-scale.workload > > > > -- > Zhengjun Xing -- Michal Hocko SUSE Labs