Javascript:SpiderMonkey:ProjectGenerationGarbageCollection: Difference between revisions
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<td>in progress (needs bug)</td> | <td>in progress (needs bug)</td> | ||
<td>4.1</td> | <td>4.1</td> | ||
<td>Exactly rooted | <td>Exactly rooted js/src</td> | ||
<td>green on mozilla-inbound</td> | <td>green on mozilla-inbound</td> | ||
<td>jonco</td> | <td>jonco</td> | ||
| Line 157: | Line 157: | ||
<p>12 weeks started | <p>12 weeks started | ||
</p> | </p> | ||
<ul><li> | <ul><li> Dynamic rooting analysis on tbpl (sfink) - done | ||
<ul><li> | <ul><li> Unhidden on inbound</li></ul> | ||
</li></ul> | |||
</li><li> Get the root analysis build green - done | </li><li> Get the root analysis build green - done | ||
<ul><li> Get jit-tests green <span class="fck_mw_template"><span class="fck_mw_template">{{bug|745742}}</span></span> | <ul><li> Get jit-tests green <span class="fck_mw_template"><span class="fck_mw_template">{{bug|745742}}</span></span> | ||
| Line 175: | Line 174: | ||
<ul><li> Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks | <ul><li> Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks | ||
</li><li> Optimize all discovered over-rooting (~100) | </li><li> Optimize all discovered over-rooting (~100) | ||
</li><li> Automate static analysis <span class="fck_mw_template"><span class="fck_mw_template">{{bug|834912}}</span></span> (sfink | </li><li> Automate static analysis <span class="fck_mw_template"><span class="fck_mw_template">{{bug|834912}}</span></span> - done (sfink) | ||
</li><li> http://people.mozilla.org/~sfink/analysis/browser/rootingHazards.txt | |||
</li><li> http://people.mozilla.org/~sfink/ | </li><li> http://people.mozilla.org/~sfink/analysis/browser/gcFunctions.txt | ||
</li><li> http://people.mozilla.org/~sfink/ | </li><li> http://people.mozilla.org/~sfink/analysis/browser/allFunctions.txt | ||
</li><li> http://people.mozilla.org/~sfink/ | |||
</li></ul> | </li></ul> | ||
</li></ul> | </li></ul> | ||
| Line 190: | Line 188: | ||
<h2> Generational Garbage Collection in the Shell </h2> | <h2> Generational Garbage Collection in the Shell </h2> | ||
<ul><li> Implement prototype algorithm (terrence) - 1 week | <ul><li> Implement prototype algorithm (terrence) - 1 week | ||
</li><li> This is a potential milestone: we would need to build it and test it on TBPL similar to how |r| works now -- |GGCJS|. | </li><li> This is a potential milestone: we would need to build it and test it on TBPL similar to how |r| works now -- |GGCJS| - done. | ||
</li><li> Re-implement HashTable rekeying | </li><li> Re-implement HashTable rekeying | ||
<ul><li> We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks | <ul><li> We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks | ||
| Line 204: | Line 202: | ||
<ul><li> Also v8 deltablue, raytrace | <ul><li> Also v8 deltablue, raytrace | ||
</li></ul> | </li></ul> | ||
</li><li> We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf <span class="fck_mw_template"><span class="fck_mw_template">{{bug|759585}}</span></span> - 6 weeks | </li><li> We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf <span class="fck_mw_template"><span class="fck_mw_template">{{bug|759585}}</span></span> - 6 weeks - done | ||
</li><li> Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831886}}</span></span> (bhackett) - done | </li><li> Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831886}}</span></span> (bhackett) - done | ||
</li></ul> | </li></ul> | ||
Revision as of 22:43, 11 June 2013
Wiki conversion of original Google Document: https://docs.google.com/a/jamsni.com/document/d/1-GZ8F0ZabvdpCnRQaecId0yuu4QFYr5pAvnRC_KFchc/edit
Objective
Implement Generational Garbage collection in Spider Monkey. <Some goal based off V8 performance delta % on Earley Boyer benchmark>
Accountable: Naveed
Responsible: Terrence, Steve, Jon, Nicholas, evilpie and Ms2ger
Consulted: bhackett billm
Informed: Product Marketing
Tracking Bug: [meta] Implement generational garbage collection - bug 619558
Milestones
| Status | Milestone | Task | Deliverable | Assigned | Estimate | Expected | Actual |
|---|---|---|---|---|---|---|---|
| done | 1 | Rooting analysis in the shell (x64) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger | 2 weeks | 2013-03-07 | |
| pending | 2 | Rooting analysis in the shell (arm) | green on mozilla-inbound | sfink | 2 weeks | ||
| in progress | 3 | Exactly rooted shell (x64) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger | 2 weeks | 2013-03-14 | |
| pending | 4 | Exactly rooted shell (arm) | green on mozilla-inbound | sfink | 2 weeks | ||
| in progress (needs bug) | 4.1 | Exactly rooted js/src | green on mozilla-inbound | jonco | 3 weeks | 2013-05-09 | |
| in progress (Bug 706885) | 5 | GGC no-jit shell only build on TBPL (x64) | green on mozilla-inbound | terrence | 1.5 month | 2013-02-21 | 2013-04-07 |
| pending | 6 | GGC no-jit shell only build on TBPL (arm) | green on mozilla-inbound | sfink, terrence | 2 weeks | ||
| in progress (Bug 851057) | 7 | JIT support (x64) | TBPL build using JITs and Ion+Baseline+GGC displayed on AWFY | bhackett | 1 - 2 months | 2013-03-15 | |
| pending | 8 | JIT support (arm) | TBPL build using JITs and Ion+Baseline+GGC displayed on AWFY | bhackett sfink | 2 weeks | ||
| not started | 9 | Optimized GGC in shell (x64 + arm) | Ion+GGC faster than Ion-GGC on AWFY | bhackett | 2 - 3 months | 2013-06-01 | |
| not started | 10 | Rooting analysis in the browser | too slow to run on TBPL | sfink, jonco, evilpie, Ms2ger, terrence | 2 - 3 months | 2013-06-01 | |
| in progress | 11 | Exactly rooted browser (x64 + arm) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger, terrence | 2 - 4 month | 2013-07-01 | |
| not started | 12 | GGC in the browser (x64 + arm) | green on AWFY | terrence | 3 - 4 months | 2013-10-01 |
Steps
Exact Rooting done in JS Shell bug 753203
12 weeks started
- Dynamic rooting analysis on tbpl (sfink) - done
- Unhidden on inbound
- Get the root analysis build green - done
- Get jit-tests green bug 745742
- Get js ref tests green
- Get jsapi-tests green bug 831376
- Rooting analysis fuzz bugs bug 773746
- Rely on static analysis to make this not be a whack-a-mole game
- Remove E4X - done
- Do something about JSD
- Add exact roots to stack structures - 2 weeks
- AddRoot/RemoveRoot for Heap structures - 4 weeks
- Static code analysis bug 831409
- Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks
- Optimize all discovered over-rooting (~100)
- Automate static analysis bug 834912 - done (sfink)
- http://people.mozilla.org/~sfink/analysis/browser/rootingHazards.txt
- http://people.mozilla.org/~sfink/analysis/browser/gcFunctions.txt
- http://people.mozilla.org/~sfink/analysis/browser/allFunctions.txt
JIT Integration with post barriers - 4 weeks, parallelized
- IonMonkey bug 831506 - 1 week (bhackett)
- JaegerMonkey bug 764876 - 2 days (bhackett)
- Baseline JIT bug 831507 - <ask jandem/djvj for an estimate>
Generational Garbage Collection in the Shell
- Implement prototype algorithm (terrence) - 1 week
- This is a potential milestone: we would need to build it and test it on TBPL similar to how |r| works now -- |GGCJS| - done.
- Re-implement HashTable rekeying
- We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks
- at least part of this is bug 726687
Exactly Root the Browser bug 831379 - 10 weeks
- This is a potential milestone: we would turn on exact rooting for release FF at this point. We would not get a performance boost from this (necessarily), but it would lock in our work to this point.
Performance Tuning - 4 weeks (This should probably start asap)
- Implement a Nursery bug 706885 - 1 week
- Test against V8 Earley-Boyer benchmark.
- Also v8 deltablue, raytrace
- We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf bug 759585 - 6 weeks - done
- Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable bug 831886 (bhackett) - done
Make the Post Barrier Verifier Green in the browser bug 764882
- Investigate how long it will take to do generational barriers - 1 week
- We may need to rewrite the maps in xpconnect and the browser in terms of HashTable: this could be a bunch of work.
- Make JS_IsAboutToBeFinalized indirect bug 765432 - 10 weeks
Other
- Should we establish a new benchmark specifically for GGC. (sfink votes yes)
- What would it measure? there are multiple goals, e.g. throughput/MMU/pause time
- Should we make it a public benchmark?
- What workloads should we consider?
- compartmental GC very important to us, not necessarily applicable to other implementations
- allocation rate (broken down into live vs garbage), steady behavior vs swapping between allocation + computation modes, etc.
- How can we keep our advantage on Splay benchmark
- possible to do with TI --- look at types of objects promoted from nursery to major heap, eventually start allocating them directly in the major heap
- Compacting GC - Revisit in Febuary/March - 1 Month
- Delayed until exact rooting is fully done. We can add this in if we have time in the schedule that we cannot parallelize.
Risks
- Team is responsible for many top crashers
- External rooting API has not been designed
- GGC algorithm has not been decided on - it may not be faster
- JSD1 exact rooting is lurking