Compared to 55a64368 (rio localhost; 2017-11-06) the change is in kernel:

-# Linux rio 4.13.0-1-amd64 #1 SMP Debian 4.13.4-2 (2017-10-15) x86_64 GNU/Linux
+# Linux rio 4.15.0-1-amd64 #1 SMP Debian 4.15.4-1 (2018-02-18) x86_64 GNU/Linux

and in particular 4.15 comes with PTI.

summary:

- direct disk 4K read is ~ 93µs as it was
- pagecache is now slower due to PTI: the timing changed 0.6µs -> 0.8µs
- fs1.py access is ~2% slower, probably due to PTI
- fs1.go access is much slower due to client cache being always bolted
  on: 2.4µs -> 3.8µs (serial). The time for both serial and parallel
  cases is still small.
- zeo is ~2% slower, probably due to PTI.
- neo/py/sqlite vs zhash.py is 8% faster - because we removed
  data compression from the benchmark (b9827725), however P16 time is
  not improved.
- neo/py/sqlite vs zhash.go is 40% faster - because we removed data
  compression from the benchmark and previously neo/go code was very
  inefficient at zlib decompression (924831e7, 9acb87a8, 57524491).
  However P16 time is improved only by 2-5%.
- neo/py/sql vs zhash.{py,go} - similar changes to neo/py/sqlite
- neo/go/fs1 vs zhash.py - unchanged; vs zhash.go - slower by 12% -
  probably due to PTI. zhash.go P16 case is improved by ~35% but it
  could be all noise.
- newly introduces neo/go/sqlite vs zhash.go is at ~ 80-88µs for serial
  and ~ 230-300µs for P16 latencies (neo/py/sqlite for the same vs
  zhash.go is at ~ 120-130µs for serial and ~1600µs for P16 latencies).
  Clearly neo/go/sqlite needs more work.

Full details:

$ benchstat -split dataset 20180222-rio.txt  |grep sqlite |grep 'neo.go'
rio/neo/go/sqlite/zhash.py                      230µs ± 2%
rio/neo/go/sqlite/zhash.py-P16                  937µs ± 5%
rio/neo/go/sqlite/zhash.go                     88.4µs ± 2%
rio/neo/go/sqlite/zhash.go+prefetch128         33.6µs ± 7%
rio/neo/go/sqlite/zhash.go-P16                  228µs ±39%
rio/neo/go/sqlite(!sha1)/zhash.go              79.7µs ± 3%
rio/neo/go/sqlite(!sha1)/zhash.go+prefetch128  32.2µs ± 8%
rio/neo/go/sqlite(!sha1)/zhash.go-P16           213µs ±42%
rio/neo/go/sqlite/zhash.py                      232µs ± 2%
rio/neo/go/sqlite/zhash.py-P16                 1.00ms ± 3%
rio/neo/go/sqlite/zhash.go                     79.2µs ± 2%
rio/neo/go/sqlite/zhash.go+prefetch128         29.8µs ± 8%
rio/neo/go/sqlite/zhash.go-P16                  302µs ±40%
rio/neo/go/sqlite(!sha1)/zhash.go              78.3µs ± 2%
rio/neo/go/sqlite(!sha1)/zhash.go+prefetch128  31.1µs ± 2%
rio/neo/go/sqlite(!sha1)/zhash.go-P16           311µs ±40%

$ benchstat -split dataset 20171106-time-rio-Cenabled.txt 20180222-rio.txt

name                                          old pystone/s    new pystone/s    delta
rio/pystone                                         178k ± 2%        180k ± 3%      ~     (p=0.421 n=5+5)

name                                          old time/op      new time/op      delta
rio/disk/randread/direct/4K-min                   34.0µs ± 1%      34.7µs ± 1%    +2.06%  (p=0.008 n=5+5)
rio/disk/randread/direct/4K-avg                   92.9µs ± 0%      93.2µs ± 0%    +0.37%  (p=0.024 n=5+5)
rio/disk/randread/pagecache/4K-min                 221ns ± 0%       441ns ± 0%   +99.37%  (p=0.016 n=4+5)
rio/disk/randread/pagecache/4K-avg                 637ns ± 0%       872ns ± 1%   +37.01%  (p=0.016 n=4+5)

name                                          old time/object  new time/object  delta
dataset:wczblk1-8
rio/fs1/zhash.py                                  22.3µs ± 2%      22.8µs ± 2%    +2.24%  (p=0.048 n=5+5)
rio/fs1/zhash.py-P16                              51.7µs ±72%      60.3µs ±49%      ~     (p=0.127 n=15+16)
rio/fs1/zhash.go                                  2.40µs ± 0%      3.80µs ± 0%   +58.33%  (p=0.016 n=5+4)
rio/fs1/zhash.go+prefetch128                      4.34µs ± 8%      4.10µs ± 2%      ~     (p=0.246 n=5+5)
rio/fs1/zhash.go-P16                              3.58µs ±24%      6.79µs ±19%   +90.01%  (p=0.000 n=16+14)
rio/zeo/zhash.py                                   336µs ± 2%       342µs ± 2%    +1.82%  (p=0.040 n=5+5)
rio/zeo/zhash.py-P16                              1.61ms ±19%      1.64ms ±20%      ~     (p=0.423 n=16+16)
rio/neo/py/sqlite/zhash.py                         304µs ± 6%       279µs ± 3%    -8.11%  (p=0.016 n=5+5)
rio/neo/py/sqlite/zhash.py-P16                    2.19ms ± 0%      2.28ms ± 1%    +4.16%  (p=0.000 n=13+15)
rio/neo/py/sqlite/zhash.go                         248µs ± 1%       147µs ± 2%   -40.70%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.go+prefetch128             125µs ± 1%       125µs ± 2%      ~     (p=0.651 n=5+5)
rio/neo/py/sqlite/zhash.go-P16                    1.76ms ±13%      1.73ms ±14%    -1.72%  (p=0.002 n=16+16)
rio/neo/py(!log)/sqlite/zhash.py                   291µs ± 2%       267µs ± 1%    -8.20%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.py-P16              2.01ms ± 2%      2.01ms ± 1%      ~     (p=0.545 n=16+15)
rio/neo/py(!log)/sqlite/zhash.go                   231µs ± 1%       130µs ± 2%   -43.54%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go+prefetch128       110µs ± 2%       112µs ± 4%      ~     (p=0.222 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go-P16              1.62ms ± 7%      1.62ms ± 0%    +0.18%  (p=0.029 n=16+11)
rio/neo/py/sql/zhash.py                            325µs ± 4%       294µs ± 1%    -9.50%  (p=0.029 n=4+4)
rio/neo/py/sql/zhash.py-P16                       2.88ms ± 1%      2.85ms ± 1%    -0.94%  (p=0.000 n=15+15)
rio/neo/py/sql/zhash.go                            275µs ± 2%       169µs ± 3%   -38.39%  (p=0.008 n=5+5)
rio/neo/py/sql/zhash.go+prefetch128                154µs ± 3%       154µs ± 4%      ~     (p=1.000 n=5+5)
rio/neo/py/sql/zhash.go-P16                       2.30ms ± 8%      2.19ms ±11%    -5.03%  (p=0.009 n=16+16)
rio/neo/py(!log)/sql/zhash.py                      313µs ± 4%       285µs ± 5%    -8.95%  (p=0.029 n=4+4)
rio/neo/py(!log)/sql/zhash.py-P16                 2.56ms ± 1%      2.47ms ± 1%    -3.45%  (p=0.000 n=15+14)
rio/neo/py(!log)/sql/zhash.go                      258µs ± 1%       152µs ± 1%   -41.05%  (p=0.016 n=5+4)
rio/neo/py(!log)/sql/zhash.go+prefetch128          139µs ± 1%       137µs ± 3%      ~     (p=0.151 n=5+5)
rio/neo/py(!log)/sql/zhash.go-P16                 2.21ms ± 5%      1.98ms ± 0%   -10.19%  (p=0.000 n=16+11)
rio/neo/go/fs1/zhash.py                            190µs ± 3%       190µs ± 4%      ~     (p=1.000 n=5+5)
rio/neo/go/fs1/zhash.py-P16                        784µs ± 9%       755µs ± 7%    -3.69%  (p=0.018 n=16+16)
rio/neo/go/fs1/zhash.go                           52.0µs ± 1%      58.0µs ± 3%   +11.55%  (p=0.008 n=5+5)
rio/neo/go/fs1/zhash.go+prefetch128               26.6µs ± 5%      24.9µs ± 4%      ~     (p=0.087 n=5+5)
rio/neo/go/fs1/zhash.go-P16                        256µs ± 6%       164µs ±50%   -36.13%  (p=0.000 n=15+16)
rio/neo/go/fs1(!sha1)/zhash.go                    35.3µs ± 4%      37.3µs ± 2%    +5.73%  (p=0.008 n=5+5)
rio/neo/go/fs1(!sha1)/zhash.go+prefetch128        17.3µs ± 2%      16.3µs ± 2%    -6.00%  (p=0.008 n=5+5)
rio/neo/go/fs1(!sha1)/zhash.go-P16                 152µs ±13%       118µs ±51%   -22.57%  (p=0.000 n=13+16)
dataset:prod1-1024
rio/fs1/zhash.py                                  18.9µs ± 1%      18.9µs ± 2%      ~     (p=0.825 n=5+5)
rio/fs1/zhash.py-P16                              58.0µs ±52%      56.2µs ±32%      ~     (p=0.926 n=16+16)
rio/fs1/zhash.go                                  1.30µs ± 0%      2.80µs ± 0%  +115.38%  (p=0.016 n=4+5)
rio/fs1/zhash.go+prefetch128                      2.78µs ±14%      2.70µs ± 0%      ~     (p=0.413 n=5+4)
rio/fs1/zhash.go-P16                              2.24µs ±16%      6.59µs ±43%  +194.93%  (p=0.000 n=14+16)
rio/zeo/zhash.py                                   302µs ± 7%       294µs ± 6%      ~     (p=0.310 n=5+5)
rio/zeo/zhash.py-P16                              1.44ms ±11%      1.46ms ± 3%      ~     (p=0.892 n=15+13)
rio/neo/py/sqlite/zhash.py                         269µs ± 1%       275µs ± 1%    +2.51%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.py-P16                    2.19ms ± 0%      2.34ms ± 0%    +6.70%  (p=0.000 n=16+13)
rio/neo/py/sqlite/zhash.go                         158µs ± 1%       140µs ± 3%   -11.68%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.go+prefetch128             116µs ± 3%       118µs ± 1%      ~     (p=0.111 n=5+5)
rio/neo/py/sqlite/zhash.go-P16                    1.90ms ± 0%      1.81ms ± 7%    -4.58%  (p=0.000 n=14+16)
rio/neo/py(!log)/sqlite/zhash.py                   259µs ± 4%       262µs ± 3%      ~     (p=0.690 n=5+5)
rio/neo/py(!log)/sqlite/zhash.py-P16              1.89ms ± 1%      2.04ms ± 0%    +7.53%  (p=0.000 n=15+15)
rio/neo/py(!log)/sqlite/zhash.go                   142µs ± 1%       123µs ± 2%   -13.14%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go+prefetch128       101µs ± 2%       103µs ± 1%    +2.37%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go-P16              1.57ms ± 0%      1.61ms ± 5%      ~     (p=0.089 n=13+16)
rio/neo/py/sql/zhash.py                            337µs ±43%       298µs ± 3%      ~     (p=0.556 n=5+4)
rio/neo/py/sql/zhash.py-P16                       2.73ms ± 0%      2.86ms ± 0%    +4.74%  (p=0.000 n=15+15)
rio/neo/py/sql/zhash.go                            186µs ± 3%       164µs ± 4%   -11.92%  (p=0.008 n=5+5)
rio/neo/py/sql/zhash.go+prefetch128                145µs ± 2%       147µs ± 2%      ~     (p=0.095 n=5+5)
rio/neo/py/sql/zhash.go-P16                       2.29ms ± 6%      2.27ms ± 6%    -1.19%  (p=0.002 n=16+16)
rio/neo/py(!log)/sql/zhash.py                      293µs ± 4%       287µs ± 2%      ~     (p=0.343 n=4+4)
rio/neo/py(!log)/sql/zhash.py-P16                 2.47ms ± 0%      2.51ms ± 1%    +1.61%  (p=0.000 n=15+15)
rio/neo/py(!log)/sql/zhash.go                      168µs ± 1%       146µs ± 2%   -13.49%  (p=0.008 n=5+5)
rio/neo/py(!log)/sql/zhash.go+prefetch128          130µs ± 2%       127µs ± 2%      ~     (p=0.056 n=5+5)
rio/neo/py(!log)/sql/zhash.go-P16                 2.08ms ± 3%      2.00ms ± 4%    -3.98%  (p=0.009 n=16+16)
rio/neo/go/fs1/zhash.py                            181µs ± 5%       189µs ± 9%      ~     (p=0.079 n=5+5)
rio/neo/go/fs1/zhash.py-P16                        714µs ± 6%       711µs ± 3%      ~     (p=0.861 n=15+16)
rio/neo/go/fs1/zhash.go                           36.9µs ± 3%      41.8µs ± 2%   +13.21%  (p=0.008 n=5+5)
rio/neo/go/fs1/zhash.go+prefetch128               16.5µs ± 1%      16.8µs ± 3%      ~     (p=0.103 n=5+5)
rio/neo/go/fs1/zhash.go-P16                        239µs ± 4%       195µs ± 4%   -18.37%  (p=0.000 n=15+13)
rio/neo/go/fs1(!sha1)/zhash.go                    32.7µs ± 7%      36.3µs ± 2%   +11.07%  (p=0.008 n=5+5)
rio/neo/go/fs1(!sha1)/zhash.go+prefetch128        13.5µs ± 1%      13.9µs ± 4%      ~     (p=0.056 n=5+5)
rio/neo/go/fs1(!sha1)/zhash.go-P16                 190µs ± 7%       138µs ±60%   -27.42%  (p=0.000 n=14+16)

name                                          old pystone/s    new pystone/s    delta
rio/pystone                                         178k ± 2%        180k ± 3%      ~     (p=0.421 n=5+5)

name                                          old time/op      new time/op      delta
rio/disk/randread/direct/4K-min                   34.0µs ± 1%      34.7µs ± 1%    +2.06%  (p=0.008 n=5+5)
rio/disk/randread/direct/4K-avg                   92.9µs ± 0%      93.2µs ± 0%    +0.37%  (p=0.024 n=5+5)
rio/disk/randread/pagecache/4K-min                 221ns ± 0%       441ns ± 0%   +99.37%  (p=0.016 n=4+5)
rio/disk/randread/pagecache/4K-avg                 637ns ± 0%       872ns ± 1%   +37.01%  (p=0.016 n=4+5)

name                                          old time/object  new time/object  delta
dataset:wczblk1-8
rio/fs1/zhash.py                                  22.3µs ± 2%      22.8µs ± 2%    +2.24%  (p=0.048 n=5+5)
rio/fs1/zhash.py-P16                              51.7µs ±72%      60.3µs ±49%      ~     (p=0.127 n=15+16)
rio/fs1/zhash.go                                  2.40µs ± 0%      3.80µs ± 0%   +58.33%  (p=0.016 n=5+4)
rio/fs1/zhash.go+prefetch128                      4.34µs ± 8%      4.10µs ± 2%      ~     (p=0.246 n=5+5)
rio/fs1/zhash.go-P16                              3.58µs ±24%      6.79µs ±19%   +90.01%  (p=0.000 n=16+14)
rio/zeo/zhash.py                                   336µs ± 2%       342µs ± 2%    +1.82%  (p=0.040 n=5+5)
rio/zeo/zhash.py-P16                              1.61ms ±19%      1.64ms ±20%      ~     (p=0.423 n=16+16)
rio/neo/py/sqlite/zhash.py                         304µs ± 6%       279µs ± 3%    -8.11%  (p=0.016 n=5+5)
rio/neo/py/sqlite/zhash.py-P16                    2.19ms ± 0%      2.28ms ± 1%    +4.16%  (p=0.000 n=13+15)
rio/neo/py/sqlite/zhash.go                         248µs ± 1%       147µs ± 2%   -40.70%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.go+prefetch128             125µs ± 1%       125µs ± 2%      ~     (p=0.651 n=5+5)
rio/neo/py/sqlite/zhash.go-P16                    1.76ms ±13%      1.73ms ±14%    -1.72%  (p=0.002 n=16+16)
rio/neo/py(!log)/sqlite/zhash.py                   291µs ± 2%       267µs ± 1%    -8.20%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.py-P16              2.01ms ± 2%      2.01ms ± 1%      ~     (p=0.545 n=16+15)
rio/neo/py(!log)/sqlite/zhash.go                   231µs ± 1%       130µs ± 2%   -43.54%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go+prefetch128       110µs ± 2%       112µs ± 4%      ~     (p=0.222 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go-P16              1.62ms ± 7%      1.62ms ± 0%    +0.18%  (p=0.029 n=16+11)
rio/neo/py/sql/zhash.py                            325µs ± 4%       294µs ± 1%    -9.50%  (p=0.029 n=4+4)
rio/neo/py/sql/zhash.py-P16                       2.88ms ± 1%      2.85ms ± 1%    -0.94%  (p=0.000 n=15+15)
rio/neo/py/sql/zhash.go                            275µs ± 2%       169µs ± 3%   -38.39%  (p=0.008 n=5+5)
rio/neo/py/sql/zhash.go+prefetch128                154µs ± 3%       154µs ± 4%      ~     (p=1.000 n=5+5)
rio/neo/py/sql/zhash.go-P16                       2.30ms ± 8%      2.19ms ±11%    -5.03%  (p=0.009 n=16+16)
rio/neo/py(!log)/sql/zhash.py                      313µs ± 4%       285µs ± 5%    -8.95%  (p=0.029 n=4+4)
rio/neo/py(!log)/sql/zhash.py-P16                 2.56ms ± 1%      2.47ms ± 1%    -3.45%  (p=0.000 n=15+14)
rio/neo/py(!log)/sql/zhash.go                      258µs ± 1%       152µs ± 1%   -41.05%  (p=0.016 n=5+4)
rio/neo/py(!log)/sql/zhash.go+prefetch128          139µs ± 1%       137µs ± 3%      ~     (p=0.151 n=5+5)
rio/neo/py(!log)/sql/zhash.go-P16                 2.21ms ± 5%      1.98ms ± 0%   -10.19%  (p=0.000 n=16+11)
dataset:prod1-1024
rio/fs1/zhash.py                                  18.9µs ± 1%      18.9µs ± 2%      ~     (p=0.825 n=5+5)
rio/fs1/zhash.py-P16                              58.0µs ±52%      56.2µs ±32%      ~     (p=0.926 n=16+16)
rio/fs1/zhash.go                                  1.30µs ± 0%      2.80µs ± 0%  +115.38%  (p=0.016 n=4+5)
rio/fs1/zhash.go+prefetch128                      2.78µs ±14%      2.70µs ± 0%      ~     (p=0.413 n=5+4)
rio/fs1/zhash.go-P16                              2.24µs ±16%      6.59µs ±43%  +194.93%  (p=0.000 n=14+16)
rio/zeo/zhash.py                                   302µs ± 7%       294µs ± 6%      ~     (p=0.310 n=5+5)
rio/zeo/zhash.py-P16                              1.44ms ±11%      1.46ms ± 3%      ~     (p=0.892 n=15+13)
rio/neo/py/sqlite/zhash.py                         269µs ± 1%       275µs ± 1%    +2.51%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.py-P16                    2.19ms ± 0%      2.34ms ± 0%    +6.70%  (p=0.000 n=16+13)
rio/neo/py/sqlite/zhash.go                         158µs ± 1%       140µs ± 3%   -11.68%  (p=0.008 n=5+5)
rio/neo/py/sqlite/zhash.go+prefetch128             116µs ± 3%       118µs ± 1%      ~     (p=0.111 n=5+5)
rio/neo/py/sqlite/zhash.go-P16                    1.90ms ± 0%      1.81ms ± 7%    -4.58%  (p=0.000 n=14+16)
rio/neo/py(!log)/sqlite/zhash.py                   259µs ± 4%       262µs ± 3%      ~     (p=0.690 n=5+5)
rio/neo/py(!log)/sqlite/zhash.py-P16              1.89ms ± 1%      2.04ms ± 0%    +7.53%  (p=0.000 n=15+15)
rio/neo/py(!log)/sqlite/zhash.go                   142µs ± 1%       123µs ± 2%   -13.14%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go+prefetch128       101µs ± 2%       103µs ± 1%    +2.37%  (p=0.008 n=5+5)
rio/neo/py(!log)/sqlite/zhash.go-P16              1.57ms ± 0%      1.61ms ± 5%      ~     (p=0.089 n=13+16)
rio/neo/py/sql/zhash.py                            337µs ±43%       298µs ± 3%      ~     (p=0.556 n=5+4)
rio/neo/py/sql/zhash.py-P16                       2.73ms ± 0%      2.86ms ± 0%    +4.74%  (p=0.000 n=15+15)
rio/neo/py/sql/zhash.go                            186µs ± 3%       164µs ± 4%   -11.92%  (p=0.008 n=5+5)
rio/neo/py/sql/zhash.go+prefetch128                145µs ± 2%       147µs ± 2%      ~     (p=0.095 n=5+5)
rio/neo/py/sql/zhash.go-P16                       2.29ms ± 6%      2.27ms ± 6%    -1.19%  (p=0.002 n=16+16)
rio/neo/py(!log)/sql/zhash.py                      293µs ± 4%       287µs ± 2%      ~     (p=0.343 n=4+4)
rio/neo/py(!log)/sql/zhash.py-P16                 2.47ms ± 0%      2.51ms ± 1%    +1.61%  (p=0.000 n=15+15)
rio/neo/py(!log)/sql/zhash.go                      168µs ± 1%       146µs ± 2%   -13.49%  (p=0.008 n=5+5)
rio/neo/py(!log)/sql/zhash.go+prefetch128          130µs ± 2%       127µs ± 2%      ~     (p=0.056 n=5+5)
rio/neo/py(!log)/sql/zhash.go-P16                 2.08ms ± 3%      2.00ms ± 4%    -3.98%  (p=0.009 n=16+16)