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JS Team Update 11/1

For a while, I was pretty swamped, with not enough time to do a regular team newsletter. And then, I figured I’d have to go back over the past 2 months of activity to sort out everything that happened so I could write a proper giant update. But, I realize that’s way too hard and I’ll never get to it, so instead I’ll just do a brief update as of today:

  • Terrence Cole joined the team to work on GC efforts. As his first key project, he’s been working on a patch to release pages of the JS heap that are not in use back to the OS, to reduce memory fragmentation.
  • Jan de Mooij just joined the IonMonkey team as a full-time employee working out of the Netherlands. Jan, of course, was a key volunteer contributor to both the JägerMonkey and Type Inference (TI) projects.
  • Speaking of TI, it’s about to go to Beta and everything looks good, in both performance and stability. Brian Hackett has been working hard to fix critical bugs and performance regressions that were discovered in Nightly and Aurora.
  • Brian also did work in the JM branch to make objects and functions smaller, which will help a bit with memory usage, but mostly for performance–less data to initialize and being able to hold more objects in cache. This is waiting for incremental GC before landing to mozilla-central.
  • Incremental GC is getting close–it’s planned to land by the end of 2011. GC tuning and memory reporter improvements continue.
  • IonMonkey, finishing ES5 compat, finishing new debugger support, and the JS stack profiler are all ongoing.
  • We are spinning up work on ECMAScript Harmony–Jason Orendorff is starting with modules. He’s doing some front-end refactoring first to ease the path.


Comment from Daniel
Time: November 1, 2011, 2:10 pm

Thanks for the update! It’s much appreciated. I’m looking forward to see the incremental GC in action soon 🙂

Comment from Funtom
Time: November 1, 2011, 2:45 pm

Great news. Looking forward to see JM+TI crossing the green track at AWFY.

Comment from Nicholas Nethercote
Time: November 1, 2011, 4:43 pm

Turns out that the objshrink work is blocked by GC write barriers, which should be finished in the next 2 weeks or so, not incremental GC. And if Bill doesn’t finish them in 2 weeks, he’ll let objshrink jump ahead.

Comment from Nicholas Nethercote
Time: November 1, 2011, 5:44 pm

BTW, it’s spelt “Terrence”, judging from his IRC nick 🙂

Comment from Ed
Time: November 1, 2011, 11:12 pm

Finally news on incremental GC… cant wait for it to land.

Comment from Cristian Silaghi
Time: November 8, 2011, 12:07 pm

Can you “land” some preview builds with latest changes on JS engine? Can you make a build per week/month? I really want to test Firefox with IonMonkey. 🙂