Charles Oliver Nutter created JRUBY-6330: --------------------------------------------
Summary: Performance degradation in Time.strptime with invokedynamic Key: JRUBY-6330 URL: https://jira.codehaus.org/browse/JRUBY-6330 Project: JRuby Issue Type: Bug Components: Compiler, Performance Affects Versions: JRuby 1.7 Reporter: Charles Oliver Nutter There appears to be a rather severe degradation in performance on the Ruby-based Time.strptime when running on JRuby master with invokedynamic. {noformat} Java 7 without invokedynamic: Time.strptime 65.929000 0.000000 65.929000 ( 65.930000) Java 7 with invokedynamic: Time.strptime 196.221000 0.000000 196.221000 (196.221000) {noformat} I investigated a bit. The offending method is eventually Date._strptime_i in date/format.rb. It's a pretty dreadful method...very large, with a giant case/when statement with String cases. It appears that it is actually compiled by the JVM JIT, but it's so large I'm sure many of the dynamic calls are not inlining. I suspect that because non-inlined invokedynamic calls are still very slow, performance suffers. This lends some weight to building in a tiered failover that would limit invokedynamic use to smaller methods, failing over to normal CallSite invocation and eventually full interpretation. The compiled version using our simpler inline caching logic manages to perform around 3x faster...a vast margin. The benchmark is here: https://gist.github.com/1586648 -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://jira.codehaus.org/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe from this list, please visit: http://xircles.codehaus.org/manage_email