Comment #7 on issue 1662 by [email protected]: Excessive overhead of
String.replace(/a/g,'b')
http://code.google.com/p/v8/issues/detail?id=1662
Apologies... the 40% comes from the attached test. It does replace() 100
times to dilute all other operations. In vanilla 9145, AtomExec ate 30%,
see the profile and the test case attached.
$ ./d8 --prof test-d8.js
started: String.replace performance test
1mln char array composed in 34ms
array joined in 4ms
1mln symbol string: all symbols replaced 100 TIMES in 8101ms
too smart optimizations excluded 1000000 1000000 1000000
[C++]:
ticks total nonlib name
2487 30.7% 30.8%
v8::internal::RegExpImpl::AtomExec(v8::internal::Handle<v8::internal::JSRegExp>,
v8::internal::Handle<v8::internal::String>, int,
v8::internal::Handle<v8::internal::JSArray>)
928 11.5% 11.5%
v8::internal::CompiledReplacement::Apply(v8::internal::ReplacementStringBuilder*,
int, int, v8::internal::Handle<v8::internal::JSArray>)
664 8.2% 8.2% v8::internal::String::GetFlatContent()
Attachments:
v8.log.gz 40.2 KB
test-d8-100.js 611 bytes
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