commit fc5edaca30801f2d1acb7a9d39943638e6d4c1c1
author Ben Burkert <ben@benburkert.com> Mon May 21 12:56:02 2018 -0700
committer Brad Fitzpatrick <bradfitz@golang.org> Wed Sep 05 09:26:47 2018 +0000
tree 5feb0e4a0b98441f0c1962dc7b949be421e7dff1
parent f94de9c9fbed2a8d52a84b565c54da6efb015c4d

net: use splice(2) on Linux when reading from UnixConn, rework splice tests

Rework the splice tests and benchmarks. Move the reading and writing of
the spliced connections to child processes so that the I/O is not part
of benchmarks or profiles.

Enable the use of splice(2) when reading from a unix connection and
writing to a TCP connection. The updated benchmarks show a performance
gain when using splice(2) to copy large chunks of data that the original
benchmark did not capture.

  name                          old time/op    new time/op    delta
  Splice/tcp-to-tcp/1024-8        5.01µs ± 2%    5.08µs ± 3%      ~     (p=0.068 n=8+10)
  Splice/tcp-to-tcp/2048-8        4.76µs ± 5%    4.65µs ± 3%    -2.36%  (p=0.015 n=9+8)
  Splice/tcp-to-tcp/4096-8        4.91µs ± 2%    4.98µs ± 5%      ~     (p=0.315 n=9+10)
  Splice/tcp-to-tcp/8192-8        5.50µs ± 4%    5.44µs ± 3%      ~     (p=0.758 n=7+9)
  Splice/tcp-to-tcp/16384-8       7.65µs ± 7%    6.53µs ± 3%   -14.65%  (p=0.000 n=10+9)
  Splice/tcp-to-tcp/32768-8       15.3µs ± 7%     8.5µs ± 5%   -44.21%  (p=0.000 n=10+10)
  Splice/tcp-to-tcp/65536-8       30.0µs ± 6%    15.7µs ± 1%   -47.58%  (p=0.000 n=10+8)
  Splice/tcp-to-tcp/131072-8      59.2µs ± 2%    27.4µs ± 5%   -53.75%  (p=0.000 n=9+9)
  Splice/tcp-to-tcp/262144-8       121µs ± 4%      54µs ±19%   -55.56%  (p=0.000 n=9+10)
  Splice/tcp-to-tcp/524288-8       247µs ± 6%     108µs ±12%   -56.34%  (p=0.000 n=10+10)
  Splice/tcp-to-tcp/1048576-8      490µs ± 4%     199µs ±12%   -59.31%  (p=0.000 n=8+10)
  Splice/unix-to-tcp/1024-8       1.20µs ± 2%    1.35µs ± 7%   +12.47%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/2048-8       1.33µs ±12%    1.57µs ± 4%   +17.85%  (p=0.000 n=9+10)
  Splice/unix-to-tcp/4096-8       2.24µs ± 4%    1.67µs ± 4%   -25.14%  (p=0.000 n=9+10)
  Splice/unix-to-tcp/8192-8       4.59µs ± 8%    2.20µs ±10%   -52.01%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/16384-8      8.46µs ±13%    3.48µs ± 6%   -58.91%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/32768-8      18.5µs ± 9%     6.1µs ± 9%   -66.99%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/65536-8      35.9µs ± 7%    13.5µs ± 6%   -62.40%  (p=0.000 n=10+9)
  Splice/unix-to-tcp/131072-8     79.4µs ± 6%    25.7µs ± 4%   -67.62%  (p=0.000 n=10+9)
  Splice/unix-to-tcp/262144-8      157µs ± 4%      54µs ± 8%   -65.63%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/524288-8      311µs ± 3%     107µs ± 8%   -65.74%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/1048576-8     643µs ± 4%     185µs ±32%   -71.21%  (p=0.000 n=10+10)

  name                          old speed      new speed      delta
  Splice/tcp-to-tcp/1024-8       204MB/s ± 2%   202MB/s ± 3%      ~     (p=0.068 n=8+10)
  Splice/tcp-to-tcp/2048-8       430MB/s ± 5%   441MB/s ± 3%    +2.39%  (p=0.014 n=9+8)
  Splice/tcp-to-tcp/4096-8       833MB/s ± 2%   823MB/s ± 5%      ~     (p=0.315 n=9+10)
  Splice/tcp-to-tcp/8192-8      1.49GB/s ± 4%  1.51GB/s ± 3%      ~     (p=0.758 n=7+9)
  Splice/tcp-to-tcp/16384-8     2.14GB/s ± 7%  2.51GB/s ± 3%   +17.03%  (p=0.000 n=10+9)
  Splice/tcp-to-tcp/32768-8     2.15GB/s ± 7%  3.85GB/s ± 5%   +79.11%  (p=0.000 n=10+10)
  Splice/tcp-to-tcp/65536-8     2.19GB/s ± 5%  4.17GB/s ± 1%   +90.65%  (p=0.000 n=10+8)
  Splice/tcp-to-tcp/131072-8    2.22GB/s ± 2%  4.79GB/s ± 4%  +116.26%  (p=0.000 n=9+9)
  Splice/tcp-to-tcp/262144-8    2.17GB/s ± 4%  4.93GB/s ±17%  +127.25%  (p=0.000 n=9+10)
  Splice/tcp-to-tcp/524288-8    2.13GB/s ± 6%  4.89GB/s ±13%  +130.15%  (p=0.000 n=10+10)
  Splice/tcp-to-tcp/1048576-8   2.09GB/s ±10%  5.29GB/s ±11%  +153.36%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/1024-8      850MB/s ± 2%   757MB/s ± 7%   -10.94%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/2048-8     1.54GB/s ±11%  1.31GB/s ± 3%   -15.32%  (p=0.000 n=9+10)
  Splice/unix-to-tcp/4096-8     1.83GB/s ± 4%  2.45GB/s ± 4%   +33.59%  (p=0.000 n=9+10)
  Splice/unix-to-tcp/8192-8     1.79GB/s ± 9%  3.73GB/s ± 9%  +108.05%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/16384-8    1.95GB/s ±13%  4.68GB/s ± 3%  +139.80%  (p=0.000 n=10+9)
  Splice/unix-to-tcp/32768-8    1.78GB/s ± 9%  5.38GB/s ±10%  +202.71%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/65536-8    1.83GB/s ± 8%  4.85GB/s ± 6%  +165.70%  (p=0.000 n=10+9)
  Splice/unix-to-tcp/131072-8   1.65GB/s ± 6%  5.10GB/s ± 4%  +208.77%  (p=0.000 n=10+9)
  Splice/unix-to-tcp/262144-8   1.67GB/s ± 4%  4.87GB/s ± 7%  +191.19%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/524288-8   1.69GB/s ± 3%  4.93GB/s ± 7%  +192.38%  (p=0.000 n=10+10)
  Splice/unix-to-tcp/1048576-8  1.63GB/s ± 3%  5.60GB/s ±44%  +243.26%  (p=0.000 n=10+9)

Change-Id: I1eae4c3459c918558c70fc42283db22ff7e0442c
Reviewed-on: https://go-review.googlesource.com/113997
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>