[ruby-core:42743] [ruby-trunk - Feature #5138] Add nonblocking IO that does not use exceptions for EOF and EWOULDBLOCK

< :前の番号 ^ :番号順リスト > :次の番号 P :前の記事（スレッド移動） N :次の記事（スレッド移動） |<:前のスレッド >|:次のスレッド ^ :返事先 _:自分への返事 >:同じ返事先を持つ記事（前） <:同じ返事先を持つ記事（後） ---:分割してスレッド表示、再表示 | :分割して（縦）スレッド表示、再表示 ~ :スレッドのフレーム消去 .:インデックス ..:インデックスのインデックス

Issue #5138 has been updated by Charles Nutter. I never got to weigh in on this thread back in the day, and I'm working on IO stuff more recently, so a few thoughts... Eric Wong wrote: > * Exceptions with the current *_nonblock methods are expensive. > > - extending with IO::Wait* increments the global VM state version This is really poor form. I'm not sure why it hasn't been fixed yet. JRuby master solves this in a neat, compatible way: instead of raising singleton EAGAIN with WaitReable or WaitWritable mixed in, we raise EAGAINReadable or EAGAINWritable, subclasses that have already done the mixing. No other changes are needed. > - backtrace generation cost In JRuby, EAGAIN does not generate a backtrace unless you pass a flag, since generally it's an "expected" exception and you don't want the backtrace anyway. How does this translate to perf? system ~/projects $ jruby eagain_bench.rb 1.553000 0.000000 1.553000 ( 1.553000) 0.673000 0.000000 0.673000 ( 0.673000) 0.667000 0.000000 0.667000 ( 0.667000) 0.669000 0.000000 0.669000 ( 0.669000) 0.696000 0.000000 0.696000 ( 0.697000) system ~/projects $ rvm 1.9.3 do ruby eagain_bench.rb 1.250000 0.150000 1.400000 ( 1.396295) 1.250000 0.150000 1.400000 ( 1.408975) 1.260000 0.150000 1.410000 ( 1.405947) 1.250000 0.150000 1.400000 ( 1.405391) 1.260000 0.150000 1.410000 ( 1.407389) system ~/projects $ rvm ruby-head do ruby eagain_bench.rb 1.310000 0.120000 1.430000 ( 1.428627) 1.300000 0.120000 1.420000 ( 1.430652) 1.310000 0.130000 1.440000 ( 1.426011) 1.310000 0.120000 1.430000 ( 1.430642) 1.310000 0.120000 1.430000 ( 1.436441) Rather well, I think. ---------------------------------------- Feature #5138: Add nonblocking IO that does not use exceptions for EOF and EWOULDBLOCK https://bugs.ruby-lang.org/issues/5138 Author: Yehuda Katz Status: Open Priority: Normal Assignee: Yukihiro Matsumoto Category: core Target version: 1.9.4 The current Ruby I/O classes have non-blocking methods (read_nonblock and write_nonblock). These methods will never block, and if they would block, they raise an exception instead (IO::WaitReadable or IO::WaitWritable). In addition, if the IO is at EOF, they raise an EOFError. These exceptions are raised repeatedly in virtually every use of the non-blocking methods. This patch adds a pair of methods (try_read_nonblock and try_write_nonblock) that have the same semantics as the existing methods, but they return Symbols instead of raising exceptions for these routine cases: * :read_would_block * :write_would_block * :eof The patch contains updates for IO, StringIO, and OpenSSL. The updates are fully documented and tested. -- http://bugs.ruby-lang.org/