Platform/Features/Incremental GC/TestPlan
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Contents
Incremental Garbage Collection
| Feature | Status | Release Target | Dev Lead | QA Lead | QA Status |
| Incremental GC | Landed | Firefox 16 | Bill McCloskey | Ioana Budnar | Signed off on Aurora |
Summary
- Garbage collection time is divided into short increments. Overall, the same amount of time is spent doing garbage collection, but each individual pause is shorter.
References
Use Cases
- Use Firefox with incremental garbage collection enabled:
- Dynamic content on the web should have more tolerable pauses (possibly go from noticeable pauses to ones the user cannot notice).
- Most GCs, if not all, should be incremental.
- Incremental GC parameters should have acceptable values (slices with Marks <=20ms, Max Pauses <=16ms, or at least shorter than the total for Mark).
- Disable incremental garbage collection.
Test Cases
- The test cases for this feature can be viewed here.
Important Bugs
| ID | Summary | Priority | Status |
|---|---|---|---|
| 728686 | JS_NewPropertyIterator disables IGC | -- | VERIFIED |
| 728692 | Javascript becomes slow after Incremental GC gets disabled | -- | RESOLVED |
| 728976 | Debug-only incremental GC crash [@ js::ReentrancyGuard::ReentrancyGuard] | -- | RESOLVED |
| 729773 | [IncrementalGC] "Assertion failure: IsMarkedOrAllocated(static_cast<Cell *>(thing))" with adoptNode, gczeal(4) | -- | RESOLVED |
| 730853 | If incremental GC or compartment GC runs all the time, CC never runs | -- | VERIFIED |
| 734946 | Disable incremental GC for Firefox 13 | -- | VERIFIED |
| 735099 | Re-enable incremental GC on desktop platforms | -- | RESOLVED |
| 735944 | about:support says "incremental gc: 1" when javascript.options.mem.gc_incremental is disabled | -- | VERIFIED |
| 752098 | Crashes on MemBench with incremental GC enabled | -- | RESOLVED |
| 759522 | OOM during mochitest-other | -- | RESOLVED |
| 761739 | incremental GCs are very rare | -- | RESOLVED |
| 768688 | Disable incremental GC for Firefox 15; re-enable compartment GCs | -- | RESOLVED |
12 Total; 0 Open (0%); 8 Resolved (66.67%); 4 Verified (33.33%);
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.
- Firefox 16.0 Aurora - 2012-07-20
- 30%-40% of the IGCs have long slices, but they all have acceptable Mark values (<20ms).
- 10%-20% of the IGCs have Max Pause longer than the total for Mark.
