Messages in this thread | | | From | "Huang\, Ying" <> | Subject | Re: [LKP] [lkp] [perf powerpc] 18d1796d0b: [No primary change] | Date | Wed, 26 Oct 2016 10:09:23 +0800 |
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Peter Zijlstra <peterz@infradead.org> writes:
> On Tue, Oct 25, 2016 at 02:40:13PM +0800, kernel test robot wrote: >> [will-it-scale] perf-stat.branch-miss-rate +7.4% regression >> Reply-To: kernel test robot <xiaolong.ye@intel.com> >> User-Agent: Heirloom mailx 12.5 6/20/10 >> >> >> FYI, we noticed a +7.4% regression of perf-stat.branch-miss-rate due to commit: >> >> commit 18d1796d0b45762ec6f58c5ed2ad3f7510ffbaa9 ("perf powerpc: Don't call perf_event_disable from atomic context") >> https://github.com/0day-ci/linux Jiri-Olsa/perf-powerpc-Don-t-call-perf_event_disable-from-atomic-context/20161006-203500 >> >> in testcase: will-it-scale >> on test machine: 32 threads Intel(R) Xeon(R) CPU E5-2680 0 @ 2.70GHz with 64G memory >> with following parameters: >> >> test: poll2 >> cpufreq_governor: performance >> >> Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two. > >> Details are as below: >> --------------------------------------------------------------------------------------------------> >> >> >> To reproduce: >> >> git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git >> cd lkp-tests >> bin/lkp install job.yaml # job file is attached in this email >> bin/lkp run job.yaml >> >> ========================================================================================= >> compiler/cpufreq_governor/kconfig/rootfs/tbox_group/test/testcase: >> gcc-6/performance/x86_64-rhel-7.2/debian-x86_64-2016-08-31.cgz/lkp-sb03/poll2/will-it-scale >> >> commit: >> 41aad2a6d4 (" perf/core improvements and fixes:") >> 18d1796d0b ("perf powerpc: Don't call perf_event_disable from atomic context") >> >> 41aad2a6d4fcdda8 18d1796d0b45762ec6f58c5ed2 >> ---------------- -------------------------- >> fail:runs %reproduction fail:runs >> | | | >> %stddev %change %stddev >> \ | \ >> 0.19 . 0% +7.4% 0.21 . 0% perf-stat.branch-miss-rate% >> 9.591e+09 . 1% +9.1% 1.047e+10 . 0% perf-stat.branch-misses >> 1.962e+09 . 0% +2.3% 2.008e+09 . 1% perf-stat.cache-references >> 51.18 . 2% +5.6% 54.06 . 1% perf-stat.iTLB-load-miss-rate% >> 46430577 . 5% -6.9% 43241506 . 2% perf-stat.iTLB-loads >> 9.90 . 4% +9.3% 10.82 . 4% turbostat.Pkg%pc2 >> 62066 . 24% +34.7% 83582 . 11% numa-meminfo.node1.Active >> 49531 . 30% +42.9% 70778 . 13% numa-meminfo.node1.Active(anon) >> 27883 .100% -100.0% 0.00 . -1% latency_stats.avg.proc_cgroup_show.proc_single_show.seq_read.__vfs_read.vfs_read.SyS_read.do_syscall_64.return_from_SYSCALL_64 >> 27883 .100% -100.0% 0.00 . -1% latency_stats.max.proc_cgroup_show.proc_single_show.seq_read.__vfs_read.vfs_read.SyS_read.do_syscall_64.return_from_SYSCALL_64 >> 32685 . 38% +88.5% 61603 .147% latency_stats.sum.call_rwsem_down_write_failed.path_openat.do_filp_open.do_sys_open.SyS_open.entry_SYSCALL_64_fastpath >> 27883 .100% -100.0% 0.00 . -1% latency_stats.sum.proc_cgroup_show.proc_single_show.seq_read.__vfs_read.vfs_read.SyS_read.do_syscall_64.return_from_SYSCALL_64 >> 92795 . 4% -8.6% 84853 . 6% numa-vmstat.node0.numa_hit >> 92782 . 4% -8.5% 84851 . 6% numa-vmstat.node0.numa_local >> 12381 . 30% +42.9% 17694 . 13% numa-vmstat.node1.nr_active_anon >> 12381 . 30% +42.9% 17694 . 13% numa-vmstat.node1.nr_zone_active_anon >> 21.80 . 59% -69.8% 6.58 . 83% sched_debug.cpu.clock.stddev >> 21.80 . 59% -69.8% 6.58 . 83% sched_debug.cpu.clock_task.stddev >> 0.00 . 23% -34.3% 0.00 . 20% sched_debug.cpu.next_balance.stddev >> 35829 . 9% -18.4% 29221 . 6% sched_debug.cpu.nr_switches.max >> 8361 . 6% -13.4% 7243 . 7% sched_debug.cpu.nr_switches.stddev >> 8.43 . 11% -25.2% 6.30 . 12% sched_debug.cpu.nr_uninterruptible.stddev >> 18057 . 6% -14.3% 15482 . 8% sched_debug.cpu.sched_count.stddev >> > > ARGH... so what is the normal metric for this test and did that change? > And why can't I still find that? These reports suck!
There is observable changes between the benchmark (will-it-scale) scores. That is said in the subject of the mail: "[No primary change]". But apparently, that is not clear. We will improve that to make it more clear.
> The result doesn't make sense, my gcc inlines the function call, the > emitted code is very similar to the old code, with exception of one > extra symbol. > > Are you sure this isn't simple run to run variation?
The reported change is perf-stat.branch-miss-rate%, which is changed from 0.19% to 0.21%. That is too small. So, please ignore this report. We will be more careful in the future.
Best Regards, Huang, Ying
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