From: ko1@... Date: 2021-01-29T08:41:54+00:00 Subject: [ruby-core:102286] [Ruby master Bug#17497] Ractor performance issue Issue #17497 has been updated by ko1 (Koichi Sasada). quoted from https://github.com/ruby/ruby/pull/4129#issuecomment-769613184 ---- call the following methods as a task: ```ruby def task_range_inject (1..20_000_000).inject(:+) end ``` with * 4 times sequentially * 4 times sequentially with a sleeping ractor * 4 ractors in parallel on ``` 26_mini ruby 2.6.7p150 (2020-12-09 revision 67888) [x86_64-linux] 27_mini ruby 2.7.3p140 (2020-12-09 revision 9b884df6dd) [x86_64-linux] master_mini ruby 3.1.0dev (2021-01-29T05:27:53Z master 9241211538) [x86_64-linux] miniruby ruby 3.1.0dev (2021-01-29T06:21:39Z gh-4129 f996e15ff6) [x86_64-linux] 26_ruby ruby 2.6.7p150 (2020-12-09 revision 67888) [x86_64-linux] 27_ruby ruby 2.7.3p139 (2020-10-11 revision d1ba554551) [x86_64-linux] master_ruby ruby 3.1.0dev (2021-01-29T05:27:53Z master 9241211538) [x86_64-linux] ruby ruby 3.1.0dev (2021-01-29T06:21:39Z gh-4129 f996e15ff6) [x86_64-linux] ``` result: ``` user system total real serial/26_mini 0 0.000145 0.000039 2.782685 ( 2.783691) serial/27_mini 0 0.000133 0.000036 2.320257 ( 2.320305) serial/master_mini 0 0.000141 0.000039 3.756926 ( 3.756963) serial/miniruby 0 0.000136 0.000037 2.598088 ( 2.598126) serial/26_ruby 0 0.000143 0.000038 2.695175 ( 2.704443) serial/27_ruby 0 0.000139 0.000038 2.391679 ( 2.401067) serial/master_ruby 0 0.000139 0.000038 4.391577 ( 4.391626) serial/ruby 0 0.000128 0.000035 3.109923 ( 3.109991) r_serial/26_mini N/A r_serial/27_mini N/A r_serial/master_mini 1 0.000146 0.000040 5.133049 ( 5.133056) r_serial/miniruby 1 0.000133 0.000037 2.597336 ( 2.597300) r_serial/26_ruby N/A r_serial/27_ruby N/A r_serial/master_ruby 1 0.000147 0.000040 5.910876 ( 5.910907) r_serial/ruby 1 0.000135 0.000037 2.875752 ( 2.875727) r_parallel/26_mini N/A r_parallel/27_mini N/A r_parallel/master_mini 1 0.000100 0.000028 39.297123 ( 10.160359) r_parallel/miniruby 1 0.000110 0.000030 2.703400 ( 0.695634) r_parallel/26_ruby N/A r_parallel/27_ruby N/A r_parallel/master_ruby 1 0.000122 0.000034 38.941810 ( 10.072950) r_parallel/ruby 1 0.000131 0.000036 2.980137 ( 0.757672) ``` ---------------------------------------- Bug #17497: Ractor performance issue https://bugs.ruby-lang.org/issues/17497#change-90141 * Author: marcandre (Marc-Andre Lafortune) * Status: Closed * Priority: Normal * Assignee: ko1 (Koichi Sasada) * ruby -v: ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin18] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- There's a strange performance issue with Ractor (at least on MacOS, didn't run on other OS). I ran a benchmark doing 3 different types of work: * "fib": method calls (naive fibonacci calculation) * "cpu": `(0...1000).inject(:+)` * "sleep": call `sleep` I get the kind of results I was excepting for the `fib` and for sleeping, but the results for the "cpu" workload show a problem. It is so slow that my pure Ruby backport (using Threads) is 65x faster ���� on my Mac Pro (despite having 6 cores). Expected results would be 6x slower, so in that case Ractor is 400x slower than it should ���� On my MacBook (2 cores) the results are not as bad, the `cpu` workload is 3x faster with my pure-Ruby backport (only) instead of ~2x slower, so the factor is 6x too slow. ``` $ gem install backports Successfully installed backports-3.20.0 1 gem installed $ ruby ractor_test.rb :267: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues. fib: 110 ms | cpu: 22900 ms | sleep: 206 ms $ B=t ruby ractor_test.rb Using pure Ruby implementation fib: 652 ms | cpu: 337 ms | sleep: 209 ms ``` Notice the `sleep` run takes similar time, which is good, and `fib` is ~6x faster on my 6-core CPU (and ~2x faster on my 2-core MacBook), again that's good as the pure ruby version uses Threads and thus runs with a single GVL. The `cpu` version is the problem. Script is here: https://gist.github.com/marcandre/bfed626e538a3d0fc7cad38dc026cf0e -- https://bugs.ruby-lang.org/ Unsubscribe: