netdev - [linux-next:master] [tcp] 8ee602c635: lmbench3.TCP.socket.bandwidth.10MB.MB/sec -21.8% regression

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Message-ID: <202404302139.175c602f-oliver.sang@intel.com>
Date: Tue, 30 Apr 2024 21:45:24 +0800
From: kernel test robot <oliver.sang@...el.com>
To: Eric Dumazet <edumazet@...gle.com>
CC: <oe-lkp@...ts.linux.dev>, <lkp@...el.com>, Linux Memory Management List
	<linux-mm@...ck.org>, Jakub Kicinski <kuba@...nel.org>,
	<netdev@...r.kernel.org>, <ying.huang@...el.com>, <feng.tang@...el.com>,
	<fengwei.yin@...el.com>, <oliver.sang@...el.com>
Subject: [linux-next:master] [tcp]  8ee602c635:
 lmbench3.TCP.socket.bandwidth.10MB.MB/sec -21.8% regression



Hello,

kernel test robot noticed a -21.8% regression of lmbench3.TCP.socket.bandwidth.10MB.MB/sec on:


commit: 8ee602c635206ed012f979370094015857c02359 ("tcp: try to send bigger TSO packets")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master

[still regression on linux-next/master bb7a2467e6beef44a80a17d45ebf2931e7631083]


testcase: lmbench3
test machine: 48 threads 2 sockets Intel(R) Xeon(R) CPU E5-2697 v2 @ 2.70GHz (Ivy Bridge-EP) with 64G memory
parameters:

	test_memory_size: 50%
	nr_threads: 100%
	mode: development
	test: TCP
	cpufreq_governor: performance




If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@...el.com>
| Closes: https://lore.kernel.org/oe-lkp/202404302139.175c602f-oliver.sang@intel.com


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


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20240430/202404302139.175c602f-oliver.sang@intel.com

=========================================================================================
compiler/cpufreq_governor/kconfig/mode/nr_threads/rootfs/tbox_group/test/test_memory_size/testcase:
  gcc-13/performance/x86_64-rhel-8.3/development/100%/debian-12-x86_64-20240206.cgz/lkp-ivb-2ep2/TCP/50%/lmbench3

commit: 
  d5b38a71d3 ("tcp: call tcp_set_skb_tso_segs() from tcp_write_xmit()")
  8ee602c635 ("tcp: try to send bigger TSO packets")

d5b38a71d3334bc8 8ee602c635206ed012f97937009 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
     50684           -21.8%      39620        lmbench3.TCP.socket.bandwidth.10MB.MB/sec
     10.17 ± 41%     +83.6%      18.67 ± 15%  perf-c2c.HIT.remote
      0.10 ± 71%      +0.1        0.22 ± 16%  perf-profile.self.cycles-pp.__tcp_push_pending_frames
      0.66 ± 72%      +0.6        1.24 ± 14%  perf-profile.self.cycles-pp.tcp_write_xmit
    965580 ± 83%    +150.9%    2422689 ± 51%  numa-meminfo.node1.FilePages
   1617434 ± 52%     +91.0%    3089919 ± 40%  numa-meminfo.node1.MemUsed
      3863 ± 14%     +24.5%       4810 ± 11%  numa-meminfo.node1.PageTables
    612236 ±149%    +218.4%    1949210 ± 61%  numa-meminfo.node1.Unevictable
    241348 ± 83%    +150.9%     605612 ± 51%  numa-vmstat.node1.nr_file_pages
    964.36 ± 14%     +24.7%       1202 ± 10%  numa-vmstat.node1.nr_page_table_pages
    153059 ±149%    +218.4%     487302 ± 61%  numa-vmstat.node1.nr_unevictable
    153059 ±149%    +218.4%     487302 ± 61%  numa-vmstat.node1.nr_zone_unevictable
  51738871 ± 15%     +27.3%   65841641        perf-stat.i.cache-misses
      0.45 ±  7%      -7.5%       0.41        perf-stat.i.ipc
      1.29 ±  2%     +17.0%       1.51        perf-stat.overall.MPKI
      9.45            +1.9       11.39        perf-stat.overall.cache-miss-rate%
      2.67            +3.2%       2.75        perf-stat.overall.cpi
      2064 ±  2%     -11.8%       1820        perf-stat.overall.cycles-between-cache-misses
      0.37            -3.1%       0.36        perf-stat.overall.ipc
  51471548 ± 15%     +27.5%   65638078        perf-stat.ps.cache-misses




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