[ruby/prism] Use a more efficient StringIO on TruffleRuby
The stdlib StringIO is synchronized and this occurs a high overhead.
This is about twice as fast on TruffleRuby but surprisingly it is slower on JRuby.
I am not sure why but probably @ivar access and integer arithmetic
is much slower than Java field access/arithmetic on JRuby.
On CRuby interpreter it is slower, which is expected as the GVL already protects StringIO.
So we enable this only on TruffleRuby to not slow down other Rubies.
For the record here are the numbers for using the String directly, without a StringIO-like object:
ruby 3.3.0: 0.215 => 0.234 (cext: 0.062)
ruby 3.3.0 YJIT: 0.118 => 0.111 (cext: 0.053)
truffleruby native: 0.101 => 0.053
jruby 9.4.6.0: 0.162 => 0.195
jruby 9.4.6.0 indy: 0.078 => 0.082
As we can see, that extra object adds a non-trivial overhead on CRuby interpreter and JRuby.
But we need to make it possible to use StringIO and SimpleStringIO interchangeably.
Added by Eregon (Benoit Daloze) over 1 year ago
[ruby/prism] Use a more efficient StringIO on TruffleRuby
I am not sure why but probably @ivar access and integer arithmetic
is much slower than Java field access/arithmetic on JRuby.
ruby 3.3.0: 0.215 => 0.251 (cext: 0.062)
ruby 3.3.0 YJIT: 0.118 => 0.113 (cext: 0.053)
truffleruby JVM: 0.101 => 0.054
jruby 9.4.6.0: 0.162 => 0.219
jruby 9.4.6.0 indy: 0.078 => 0.086
ruby 3.3.0: 0.215 => 0.234 (cext: 0.062)
ruby 3.3.0 YJIT: 0.118 => 0.111 (cext: 0.053)
truffleruby native: 0.101 => 0.053
jruby 9.4.6.0: 0.162 => 0.195
jruby 9.4.6.0 indy: 0.078 => 0.082
As we can see, that extra object adds a non-trivial overhead on CRuby interpreter and JRuby.
But we need to make it possible to use StringIO and SimpleStringIO interchangeably.
https://github.com/ruby/prism/commit/938677cbd2