Hi, Shakeel Butt, please be noted we noticed the regression is still existing after this commit merged to mainline, we reported as https://lore.kernel.org/all/202301301057.e55dad5b-oliver.sang@xxxxxxxxx/ On Tue, Dec 06, 2022 at 10:41:00AM +0800, Huang, Ying wrote: > Shakeel Butt <shakeelb@xxxxxxxxxx> writes: > > > On Sun, Dec 4, 2022 at 9:56 PM kernel test robot <yujie.liu@xxxxxxxxx> wrote: > >> > >> Greeting, > >> > >> FYI, we noticed a -5.1% regression of unixbench.score due to commit: > >> > > [...] > >> 9cd6ffa60256e931 f1a7941243c102a44e8847e3b94 > >> ---------------- --------------------------- > >> %stddev %change %stddev > >> \ | \ > >> 7917 -5.1% 7509 unixbench.score > > > > What is unixbench.score? > > Should be benchmark throughput. > > >> 10485 -12.1% 9216 unixbench.time.maximum_resident_set_size > > This should reflect accuracy change of per_cpu_counter. > > >> 37236706 -5.1% 35324104 unixbench.time.minor_page_faults > > The reduction is same as benchmark score. So I think this reflect the > nature of time-bound testing (instead of workload-bound). > > > For above two, is negative change good or bad? > > > >> 0.98 ą 20% +0.7 1.64 ą 38% perf-profile.calltrace.cycles-pp.link_path_walk.path_openat.do_filp_open.do_sys_openat2.__x64_sys_openat > >> 2.12 ą 19% +0.8 2.96 ą 13% perf-profile.calltrace.cycles-pp.handle_mm_fault.do_user_addr_fault.exc_page_fault.asm_exc_page_fault > >> 2.35 ą 13% +0.9 3.28 ą 13% perf-profile.calltrace.cycles-pp.__handle_mm_fault.handle_mm_fault.do_user_addr_fault.exc_page_fault.asm_exc_page_fault > >> 0.14 ą 74% +0.4 0.55 ą 32% perf-profile.children.cycles-pp.do_task_dead > >> 0.04 ą223% +0.4 0.47 ą 49% perf-profile.children.cycles-pp.__mmdrop > > > > Also how should I interpret the above perf-profiles? > > It appears that the changes of handle_mm_fault() and __mmdrop() are > related to the code of the commit? That is, for this specific workloads > (not so unpractical), the operations become slower? > > Best Regards, > Huang, Ying >
