On Tue, Apr 30, 2024 at 3:45 PM kernel test robot <oliver.sang@xxxxxxxxx> wrote:
>
>
>
> 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:
I do not think I can spend time on this regression.
TCP performance is very sensitive to various factors, like packet
sizes, cache sizes,
sysctl settings (/proc/sys/net/ipv4/*), application design.
Making TSO packets bigger can increase p99 latencies, that is for sure.
>
> 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@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-lkp/202404302139.175c602f-oliver.sang@xxxxxxxxx
>
>
> 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@xxxxxxxxx
>
> =========================================================================================
> 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 ą 41% +83.6% 18.67 ą 15% perf-c2c.HIT.remote
> 0.10 ą 71% +0.1 0.22 ą 16% perf-profile.self.cycles-pp.__tcp_push_pending_frames
> 0.66 ą 72% +0.6 1.24 ą 14% perf-profile.self.cycles-pp.tcp_write_xmit
> 965580 ą 83% +150.9% 2422689 ą 51% numa-meminfo.node1.FilePages
> 1617434 ą 52% +91.0% 3089919 ą 40% numa-meminfo.node1.MemUsed
> 3863 ą 14% +24.5% 4810 ą 11% numa-meminfo.node1.PageTables
> 612236 ą149% +218.4% 1949210 ą 61% numa-meminfo.node1.Unevictable
> 241348 ą 83% +150.9% 605612 ą 51% numa-vmstat.node1.nr_file_pages
> 964.36 ą 14% +24.7% 1202 ą 10% numa-vmstat.node1.nr_page_table_pages
> 153059 ą149% +218.4% 487302 ą 61% numa-vmstat.node1.nr_unevictable
> 153059 ą149% +218.4% 487302 ą 61% numa-vmstat.node1.nr_zone_unevictable
> 51738871 ą 15% +27.3% 65841641 perf-stat.i.cache-misses
> 0.45 ą 7% -7.5% 0.41 perf-stat.i.ipc
> 1.29 ą 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 ą 2% -11.8% 1820 perf-stat.overall.cycles-between-cache-misses
> 0.37 -3.1% 0.36 perf-stat.overall.ipc
> 51471548 ą 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
>
