Platform/Features/Incremental GC/TestPlan

Incremental Garbage Collection

Feature	Status	Release Target	Dev Lead	QA Lead	Status
Incremental GC	Landed	Firefox 15	Bill McCloskey	Ioana Budnar	In Progress

Summary

• Garbage collection time is divided into short increments. Overall, the same amount of time is spent doing garbage colletion, but each individual pause is shorter.

References

• Wiki page

Use Cases

• Use Firefox with incremental garbage collection enabled. When IGC is enabled, dynamic content on the web should have more tolerable pauses (possibly go from noticeable pauses to ones the user cannot notice).
• Disable incremental garbage collection.

Test Cases

• The test cases for this feature can be viewed here.

Important Bugs

• 641025 - Incremental GC
• 734946 - Disable incremental GC for Firefox 13
• 728692 - Javascript becomes slow after Incremental GC gets disabled
• 735944 - about:support says "incremental gc: 1" when javascript.options.mem.gc_incremental is disabled
• 728686 - JS_NewPropertyIterator disables IGC
• 730853 - If incremental GC or compartment GC runs all the time, CC never runs
• 752098 - Crashes on MemBench with incremental GC enabled
• 735099 - Re-enable incremental GC on desktop platforms
• 728976 - Debug-only incremental GC crash [@ js::ReentrancyGuard::ReentrancyGuard]
• 729773 - [IncrementalGC] "Assertion failure: IsMarkedOrAllocated(static_cast<Cell *>(thing))" with adoptNode, gczeal(4)
• 759522 - OOM during mochitest-other
• 761739 - Incremental GC not actually being triggered

Not Tested

• Cycle collector.

Sign off

Criteria

• All the test cases were executed.
• All the major bugs have been fixed.

Sign offs

• Firefox 13.0 Aurora - 2012-03-19
• Firefox 15.0
  • Aurora - 2012-06-08
    • bugs 761739, 728692, 728976, 729773, 759522 still not fixed.