11th March 2008

Attendees

ACTION: moh will look at GCbench test and suggest some optimizations.
ACTION: tom will see if he can find additional GC/memset tests to recommend to moh and post to test directory. maybe GCheap?
ACTION: graydon will investigate Google "Summer of Code" agenda

Moh (Vtune)

hot loops investigation:
- testsinglebyte function in stringobject.cpp creates a loop that is causing slow-down
- shingha has submitted patch for this, which needs to be approved. looks like performance has improved by 50% already.
rick asks: what are you seeing with memset?
- moh can have intel look at places where memset appears to be used a lot.
- per tom, flash player zeroes memory during initialization. if we can improve zeroing time, it improves pause times.
- ACTION: moh will look at GCbench test and suggest some optimizations.
- ACTION: tom will see if he can find additional GC/memset tests to recommend to moh and post to test directory. maybe GCheap?
- moh saw "fastzero" in tamarin-tracing but hasn't had a chance to investigate yet.
- great places for memory clearing optimizations:
  - GCheap when zeroing a block
  - GC alloc when zeroing a non-RC object
- freeitem in GCalloc.cpp: RC objects need to be zeroed manually. non-RC objects are zeroed automatically by memset.
- GCheap also includes some memset.
moh asks: on tamarin-central, testsinglebyte slow-down does not appear. why?
- UTF-8 is used in tamarin-tracing, which causes VM to search variable-length strings.

Jeff

still working on ECMAScript 4 spec.
chris peyer is automating the spidermonkey test running ESC on tamarin-central.
- 96% pass rate initially, so looking good!
- lars is fixing the biggest bugs
- eval references would have to be removed to run in AS3, so we're not doing that.
- chris will post automated tests to buildbot when done.

Tom

noticed that some mozilla folks are participating in google's "summer of code" -- would be cool to get some tamarin stuff on the agenda.
ACTION: graydon will investigate

Graydon