Re: [PATCH net-next 4/4] tcp: use RCU lookup in __inet_hash_connect()

[kernel test robot <oliver.sang@intel.com>]

Hello,

kernel test robot noticed a 6.9% improvement of stress-ng.sockmany.ops_per_sec on:


commit: ba6c94b99d772f431fd589dd2cd606b59063557b ("[PATCH net-next 4/4] tcp: use RCU lookup in __inet_hash_connect()")
url: https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/tcp-use-RCU-in-__inet-6-_check_established/20250302-204711
base: https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git f77f12010f67259bd0e1ad18877ed27c721b627a
patch link: https://lore.kernel.org/all/20250302124237.3913746-5-edumazet@google.com/
patch subject: [PATCH net-next 4/4] tcp: use RCU lookup in __inet_hash_connect()

testcase: stress-ng
config: x86_64-rhel-9.4
compiler: gcc-12
test machine: 224 threads 2 sockets Intel(R) Xeon(R) Platinum 8480CTDX (Sapphire Rapids) with 256G memory
parameters:

	nr_threads: 100%
	testtime: 60s
	test: sockmany
	cpufreq_governor: performance






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


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250310/202503102159.5f78c207-lkp@intel.com

=========================================================================================
compiler/cpufreq_governor/kconfig/nr_threads/rootfs/tbox_group/test/testcase/testtime:
  gcc-12/performance/x86_64-rhel-9.4/100%/debian-12-x86_64-20240206.cgz/lkp-spr-r02/sockmany/stress-ng/60s

commit: 
  4f97f75a5b ("tcp: add RCU management to inet_bind_bucket")
  ba6c94b99d ("tcp: use RCU lookup in __inet_hash_connect()")

4f97f75a5bfa79ba ba6c94b99d772f431fd589dd2cd 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
   1742139 ± 89%     -91.6%     146373 ± 56%  numa-meminfo.node1.Unevictable
      0.61 ±  3%      +0.1        0.71 ±  3%  mpstat.cpu.all.irq%
      0.42            +0.0        0.46 ±  2%  mpstat.cpu.all.usr%
    435534 ± 89%     -91.6%      36593 ± 56%  numa-vmstat.node1.nr_unevictable
    435534 ± 89%     -91.6%      36593 ± 56%  numa-vmstat.node1.nr_zone_unevictable
   4057584            +7.0%    4340521        stress-ng.sockmany.ops
     67264            +6.9%      71933        stress-ng.sockmany.ops_per_sec
    604900           +12.3%     679404 ±  4%  perf-c2c.DRAM.local
     42998 ±  2%     -55.7%      19034 ±  3%  perf-c2c.HITM.local
     13764 ±  4%     -95.2%     663.67 ± 13%  perf-c2c.HITM.remote
     56762 ±  2%     -65.3%      19698 ±  4%  perf-c2c.HITM.total
   7422009           +13.2%    8403980 ±  2%  sched_debug.cfs_rq:/.avg_vruntime.max
    195564 ±  5%     +62.7%     318178 ± 10%  sched_debug.cfs_rq:/.avg_vruntime.stddev
      0.23 ±  7%     +25.4%       0.29 ±  4%  sched_debug.cfs_rq:/.h_nr_queued.stddev
     39935 ±  4%     +27.0%      50726 ± 29%  sched_debug.cfs_rq:/.load_avg.max
   7422009           +13.2%    8403980 ±  2%  sched_debug.cfs_rq:/.min_vruntime.max
    195564 ±  5%     +62.7%     318178 ± 10%  sched_debug.cfs_rq:/.min_vruntime.stddev
      0.23 ±  6%     +26.6%       0.29 ±  4%  sched_debug.cpu.nr_running.stddev
    387640            +5.9%     410501 ±  9%  proc-vmstat.nr_active_anon
    109911 ±  2%      +8.5%     119206 ±  2%  proc-vmstat.nr_mapped
    200627            +1.9%     204454        proc-vmstat.nr_shmem
    895041            +4.9%     939289        proc-vmstat.nr_slab_reclaimable
   2982921            +5.0%    3131084        proc-vmstat.nr_slab_unreclaimable
    387640            +5.9%     410501 ±  9%  proc-vmstat.nr_zone_active_anon
   2071760            +2.0%    2112591        proc-vmstat.numa_hit
   1839824            +2.2%    1880606        proc-vmstat.numa_local
   5905025            +5.2%    6210697        proc-vmstat.pgalloc_normal
   5291411 ± 12%     +11.9%    5921072        proc-vmstat.pgfree
      0.82 ± 13%     -29.0%       0.58 ±  6%  perf-sched.sch_delay.avg.ms.__cond_resched.__inet_hash_connect.tcp_v4_connect.__inet_stream_connect.inet_stream_connect
      4.50 ± 16%     +29.5%       5.83 ± 15%  perf-sched.sch_delay.max.ms.__cond_resched.generic_perform_write.shmem_file_write_iter.vfs_write.ksys_write
      0.03 ± 56%     -88.8%       0.00 ±223%  perf-sched.sch_delay.max.ms.__cond_resched.stop_one_cpu.migrate_task_to.task_numa_migrate.isra
      0.07 ±125%   +3754.0%       2.67 ± 71%  perf-sched.sch_delay.max.ms.__cond_resched.ww_mutex_lock.drm_gem_vunmap_unlocked.drm_gem_fb_vunmap.drm_atomic_helper_commit_planes
     19.83           -22.3%      15.41        perf-sched.total_wait_and_delay.average.ms
    177991           +32.7%     236147        perf-sched.total_wait_and_delay.count.ms
     19.76           -22.3%      15.35        perf-sched.total_wait_time.average.ms
      1.64 ± 12%     -28.9%       1.17 ±  6%  perf-sched.wait_and_delay.avg.ms.__cond_resched.__inet_hash_connect.tcp_v4_connect.__inet_stream_connect.inet_stream_connect
     13.69           -26.2%      10.10        perf-sched.wait_and_delay.avg.ms.schedule_timeout.inet_csk_accept.inet_accept.do_accept
      6844           +11.8%       7651 ±  3%  perf-sched.wait_and_delay.count.__cond_resched.__inet_hash_connect.tcp_v4_connect.__inet_stream_connect.inet_stream_connect
     78701           +33.6%     105168        perf-sched.wait_and_delay.count.__cond_resched.__release_sock.release_sock.__inet_stream_connect.inet_stream_connect
     81026           +35.2%     109539        perf-sched.wait_and_delay.count.schedule_timeout.inet_csk_accept.inet_accept.do_accept
      2268 ± 14%     +90.6%       4325 ±  6%  perf-sched.wait_and_delay.count.schedule_timeout.wait_woken.sk_wait_data.tcp_recvmsg_locked
      0.82 ± 12%     -28.6%       0.59 ±  6%  perf-sched.wait_time.avg.ms.__cond_resched.__inet_hash_connect.tcp_v4_connect.__inet_stream_connect.inet_stream_connect
     13.49           -26.5%       9.91        perf-sched.wait_time.avg.ms.__cond_resched.__release_sock.release_sock.tcp_sendmsg.__sys_sendto
      3.05 ±  3%     +16.5%       3.55 ±  3%  perf-sched.wait_time.avg.ms.__cond_resched.__wait_for_common.affine_move_task.__set_cpus_allowed_ptr.__sched_setaffinity
     30.10 ± 20%     -64.4%      10.72 ±113%  perf-sched.wait_time.avg.ms.do_task_dead.do_exit.do_group_exit.__x64_sys_exit_group.x64_sys_call
      1.14 ±  9%     +22.2%       1.40 ±  7%  perf-sched.wait_time.avg.ms.schedule_timeout.__wait_for_common.wait_for_completion_state.kernel_clone
     13.67           -26.3%      10.08        perf-sched.wait_time.avg.ms.schedule_timeout.inet_csk_accept.inet_accept.do_accept
      7.36 ± 57%    +103.9%      15.01 ± 27%  perf-sched.wait_time.avg.ms.syscall_exit_to_user_mode.do_syscall_64.entry_SYSCALL_64_after_hwframe.[unknown]
      0.03 ± 56%     -88.8%       0.00 ±223%  perf-sched.wait_time.max.ms.__cond_resched.stop_one_cpu.migrate_task_to.task_numa_migrate.isra
      0.07 ±125%    +4e+05%     275.31 ±115%  perf-sched.wait_time.max.ms.__cond_resched.ww_mutex_lock.drm_gem_vunmap_unlocked.drm_gem_fb_vunmap.drm_atomic_helper_commit_planes
     35.70           +15.3%      41.18        perf-stat.i.MPKI
 1.368e+10            +4.6%  1.431e+10        perf-stat.i.branch-instructions
      2.15            +0.1        2.27        perf-stat.i.branch-miss-rate%
 2.884e+08           +10.7%  3.192e+08        perf-stat.i.branch-misses
     71.62            +5.5       77.09        perf-stat.i.cache-miss-rate%
 2.377e+09           +26.3%  3.003e+09        perf-stat.i.cache-misses
 3.264e+09           +17.4%  3.832e+09        perf-stat.i.cache-references
      9.40            -8.1%       8.64        perf-stat.i.cpi
    292.27           -18.0%     239.70        perf-stat.i.cycles-between-cache-misses
 6.963e+10            +9.8%  7.645e+10        perf-stat.i.instructions
      0.12 ±  2%      +7.3%       0.13        perf-stat.i.ipc
     34.12           +15.0%      39.25        perf-stat.overall.MPKI
      2.11            +0.1        2.23        perf-stat.overall.branch-miss-rate%
     72.81            +5.5       78.36        perf-stat.overall.cache-miss-rate%
      9.07            -8.4%       8.31        perf-stat.overall.cpi
    265.92           -20.4%     211.72        perf-stat.overall.cycles-between-cache-misses
      0.11            +9.2%       0.12        perf-stat.overall.ipc
 1.345e+10            +4.6%  1.408e+10        perf-stat.ps.branch-instructions
 2.835e+08           +10.7%  3.139e+08        perf-stat.ps.branch-misses
 2.337e+09           +26.3%  2.952e+09        perf-stat.ps.cache-misses
 3.209e+09           +17.4%  3.768e+09        perf-stat.ps.cache-references
 6.849e+10            +9.8%  7.521e+10        perf-stat.ps.instructions
 4.236e+12            +9.1%  4.621e+12        perf-stat.total.instructions




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