Hello,

kernel test robot noticed a 2.9% improvement of stress-ng.dir.ops_per_sec on:


commit: f880fe6e0b4b127d6e2a007fe68bdf5651677ae2 ("btrfs: don't hold an extra reference for redirtied buffers")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

testcase: stress-ng
test machine: 36 threads 1 sockets Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz (Skylake) with 32G memory
parameters:

	nr_threads: 10%
	disk: 1SSD
	testtime: 60s
	fs: btrfs
	class: filesystem
	test: dir
	cpufreq_governor: performance






Details are as below:
-------------------------------------------------------------------------------------------------->


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        sudo bin/lkp install job.yaml           # job file is attached in this email
        bin/lkp split-job --compatible job.yaml # generate the yaml file for lkp run
        sudo bin/lkp run generated-yaml-file

        # if come across any failure that blocks the test,
        # please remove ~/.lkp and /lkp dir to run from a clean state.

=========================================================================================
class/compiler/cpufreq_governor/disk/fs/kconfig/nr_threads/rootfs/tbox_group/test/testcase/testtime:
  filesystem/gcc-12/performance/1SSD/btrfs/x86_64-rhel-8.3/10%/debian-11.1-x86_64-20220510.cgz/lkp-skl-d08/dir/stress-ng/60s

commit: 
  f18cc97845 ("btrfs: fix dirty_metadata_bytes for redirtied buffers")
  f880fe6e0b ("btrfs: don't hold an extra reference for redirtied buffers")

f18cc97845aa4ae0 f880fe6e0b4b127d6e2a007fe68 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
      0.95            -0.0        0.92        turbostat.POLL%
    288182            -2.8%     280247        perf-stat.i.context-switches
    283597            -2.7%     275809        perf-stat.ps.context-switches
      0.17 ±  8%      -0.0        0.14 ±  7%  perf-profile.children.cycles-pp.asm_sysvec_call_function_single
      0.47 ±  6%      +0.1        0.54 ±  7%  perf-profile.children.cycles-pp.kmem_cache_free
      0.44 ±  6%      +0.1        0.50 ±  7%  perf-profile.self.cycles-pp.kmem_cache_free
     13163 ±  7%     +14.0%      15004 ±  5%  vmstat.io.bo
    276099            -2.6%     269003        vmstat.system.cs
     71063            -2.1%      69559        vmstat.system.in
   2768594            +2.8%    2845876        stress-ng.dir.ops
     45973            +2.9%      47299        stress-ng.dir.ops_per_sec
   3433450 ±  3%      +7.4%    3687242 ±  2%  stress-ng.time.file_system_outputs
   7849247            -3.2%    7594350        stress-ng.time.voluntary_context_switches
     84934            -2.7%      82635        proc-vmstat.nr_active_anon
    502830 ±  3%      +7.2%     539258 ±  2%  proc-vmstat.nr_dirtied
     94444            -2.6%      92017        proc-vmstat.nr_shmem
     22572            +1.9%      23003        proc-vmstat.nr_slab_unreclaimable
    214997 ±  7%     +13.7%     244559 ±  6%  proc-vmstat.nr_written
     84934            -2.7%      82635        proc-vmstat.nr_zone_active_anon
    864336 ±  7%     +13.7%     983045 ±  6%  proc-vmstat.pgpgout




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.


-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki