linux-kernel - [lkp] [sched/fair] e210bffd39: perf-stat.cpu-migrations -36.0% decrease

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Date:	Thu, 4 Aug 2016 13:24:23 +0800
From:	kernel test robot <xiaolong.ye@...el.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Mike Galbraith <efault@....de>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>, lkp@...org
Subject: [lkp] [sched/fair]  e210bffd39: perf-stat.cpu-migrations -36.0%
 decrease


FYI, we noticed perf-stat.cpu-migrations -36.0% decrease due to commit:

commit e210bffd39d01b649c94b820c28ff112673266dd ("sched/fair: Fix and optimize the fork() path")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

in testcase: unixbench
on test machine: 16 threads Broadwell-DE with 8G memory
with following parameters:

	runtime: 300s
	nr_task: 1
	test: shell8
	cpufreq_governor: performance


Disclaimer:
Results have been estimated based on internal Intel analysis and are provided
for informational purposes only. Any difference in system hardware or software
design or configuration may affect actual performance.

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/nr_task/rootfs/runtime/tbox_group/test/testcase:
  gcc-6/performance/x86_64-rhel/1/debian-x86_64-2015-02-07.cgz/300s/lkp-bdw-de1/shell8/unixbench

commit: 
  630741fb60 ("Merge branch 'sched/urgent' into sched/core, to pick up fixes")
  e210bffd39 ("sched/fair: Fix and optimize the fork() path")

630741fb60ac4e28 e210bffd39d01b649c94b820c2 
---------------- -------------------------- 
       fail:runs  %reproduction    fail:runs
           |             |             |    
         %stddev     %change         %stddev
             \          |                \  
  12783488 ±  0%     -36.0%    8185912 ±  0%  perf-stat.cpu-migrations
     12787 ±  6%     -16.0%      10739 ±  8%  meminfo.AnonHugePages
      2.08 ± 25%     +29.4%       2.70 ±  9%  perf-profile.cycles-pp.cpuidle_enter_state.cpuidle_enter.call_cpuidle.cpu_startup_entry.rest_init
     39373 ± 80%     -82.5%       6894 ± 18%  softirqs.NET_RX
      0.36 ±  3%      +9.7%       0.40 ±  5%  turbostat.Pkg%pc2
      0.05 ±  0%      +1.0%       0.05 ±  0%  perf-stat.dTLB-store-miss-rate
    432.00 ±  6%     -22.2%     336.00 ±  8%  slabinfo.kmem_cache_node.active_objs
    432.00 ±  6%     -22.2%     336.00 ±  8%  slabinfo.kmem_cache_node.num_objs
      2071 ±157%   +1570.9%      34604 ±160%  latency_stats.max.rpc_wait_bit_killable.__rpc_wait_for_completion_task.nfs4_run_open_task.[nfsv4].nfs4_do_open.[nfsv4].nfs4_atomic_open.[nfsv4].nfs_atomic_open.path_openat.do_filp_open.do_sys_open.SyS_open.entry_SYSCALL_64_fastpath
     32.25 ± 31%  +30376.0%       9828 ± 99%  latency_stats.max.wait_on_page_bit_killable.__lock_page_or_retry.filemap_fault.__do_fault.handle_pte_fault.handle_mm_fault.__do_page_fault.do_page_fault.page_fault
      2337 ±140%   +1406.4%      35216 ±159%  latency_stats.sum.rpc_wait_bit_killable.__rpc_wait_for_completion_task.nfs4_run_open_task.[nfsv4].nfs4_do_open.[nfsv4].nfs4_atomic_open.[nfsv4].nfs_atomic_open.path_openat.do_filp_open.do_sys_open.SyS_open.entry_SYSCALL_64_fastpath
     38508 ± 19%    +147.5%      95303 ± 59%  latency_stats.sum.wait_on_page_bit_killable.__lock_page_or_retry.filemap_fault.__do_fault.handle_pte_fault.handle_mm_fault.__do_page_fault.do_page_fault.page_fault
      0.44 ±  7%     +15.8%       0.51 ±  2%  sched_debug.cfs_rq:/.nr_running.avg
     19118 ± 10%     +56.2%      29868 ± 13%  sched_debug.cpu.load.avg
     78773 ± 49%    +150.9%     197634 ± 25%  sched_debug.cpu.load.max
     25992 ± 33%    +104.0%      53024 ± 22%  sched_debug.cpu.load.stddev
      0.47 ± 10%     +22.9%       0.58 ±  5%  sched_debug.cpu.nr_running.avg
      0.52 ±  2%      +9.9%       0.57 ±  7%  sched_debug.cpu.nr_running.stddev



Thanks,
Xiaolong

View attachment "config-4.7.0-rc5-00014-ge210bff" of type "text/plain" (150960 bytes)

View attachment "job.yaml" of type "text/plain" (3985 bytes)

View attachment "reproduce" of type "text/plain" (147 bytes)