Javascript:SpiderMonkey:ProjectGenerationGarbageCollection: Difference between revisions
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<p>Wiki conversion of original Google Document: https://docs.google.com/a/jamsni.com/document/d/1-GZ8F0ZabvdpCnRQaecId0yuu4QFYr5pAvnRC_KFchc/edit | <p>Wiki conversion of original Google Document: https://docs.google.com/a/jamsni.com/document/d/1-GZ8F0ZabvdpCnRQaecId0yuu4QFYr5pAvnRC_KFchc/edit | ||
</p> | </p> | ||
== Objective == | |||
<p>Implement Generational Garbage collection in Spider Monkey. <Some goal based off V8 performance delta % on Earley Boyer benchmark></p> | <p>Implement Generational Garbage collection in Spider Monkey. <Some goal based off V8 performance delta % on Earley Boyer benchmark></p> | ||
<b>Accountable</b>: Naveed<br /> | <b>Accountable</b>: Naveed<br /> | ||
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<b>Tracking Bug:</b> [meta] Implement generational garbage collection - <span class="fck_mw_template"><span class="fck_mw_template"><span class="fck_mw_template">{{bug|619558}}</span></span></span> | <b>Tracking Bug:</b> [meta] Implement generational garbage collection - <span class="fck_mw_template"><span class="fck_mw_template"><span class="fck_mw_template">{{bug|619558}}</span></span></span> | ||
== Milestones == | |||
Original schedule | === Original schedule === | ||
{| class="wikitable" | {| class="wikitable" | ||
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|} | |} | ||
== Steps == | |||
=== Exact Rooting done in JS Shell {{bug|753203}} === | |||
<p>12 weeks started | <p>12 weeks started | ||
</p> | </p> | ||
| Line 181: | Line 183: | ||
</li></ul> | </li></ul> | ||
</li></ul> | </li></ul> | ||
=== JIT Integration with post barriers - 4 weeks, parallelized === | |||
<ul><li> IonMonkey <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831506}}</span></span> - 1 week (bhackett) | <ul><li> IonMonkey <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831506}}</span></span> - 1 week (bhackett) | ||
</li><li> JaegerMonkey <span class="fck_mw_template"><span class="fck_mw_template">{{bug|764876}}</span></span> - 2 days (bhackett) | </li><li> JaegerMonkey <span class="fck_mw_template"><span class="fck_mw_template">{{bug|764876}}</span></span> - 2 days (bhackett) | ||
</li><li> Baseline JIT <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831507}}</span></span> - <ask jandem/djvj for an estimate> | </li><li> Baseline JIT <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831507}}</span></span> - <ask jandem/djvj for an estimate> | ||
</li></ul> | </li></ul> | ||
=== Generational Garbage Collection in the Shell === | |||
<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| - done. | </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. | ||
| Line 194: | Line 200: | ||
</li></ul> | </li></ul> | ||
</li></ul> | </li></ul> | ||
=== Exactly Root the Browser <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831379}}</span></span> - 10 weeks === | |||
<ul><li> 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. | <ul><li> 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. | ||
</li></ul> | </li></ul> | ||
=== Performance Tuning - 4 weeks (This should probably start asap) === | |||
<ul><li> Implement a Nursery <span class="fck_mw_template"><span class="fck_mw_template">{{bug|706885}}</span></span> - 1 week | <ul><li> Implement a Nursery <span class="fck_mw_template"><span class="fck_mw_template">{{bug|706885}}</span></span> - 1 week | ||
</li><li> Test against V8 Earley-Boyer benchmark. | </li><li> Test against V8 Earley-Boyer benchmark. | ||
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</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> | ||
=== Make the Post Barrier Verifier Green in the browser <span class="fck_mw_template"><span class="fck_mw_template">{{bug|764882}}</span></span> === | |||
<ul><li> Investigate how long it will take to do generational barriers - 1 week | <ul><li> Investigate how long it will take to do generational barriers - 1 week | ||
</li><li> We may need to rewrite the maps in xpconnect and the browser in terms of HashTable: this could be a bunch of work. | </li><li> We may need to rewrite the maps in xpconnect and the browser in terms of HashTable: this could be a bunch of work. | ||
</li><li> Make JS_IsAboutToBeFinalized indirect <span class="fck_mw_template"><span class="fck_mw_template">{{bug|765432}}</span></span> - 10 weeks | </li><li> Make JS_IsAboutToBeFinalized indirect <span class="fck_mw_template"><span class="fck_mw_template">{{bug|765432}}</span></span> - 10 weeks | ||
</li></ul> | </li></ul> | ||
== Other == | |||
<ul><li> Should we establish a new benchmark specifically for GGC. (sfink votes yes) | <ul><li> Should we establish a new benchmark specifically for GGC. (sfink votes yes) | ||
<ul><li> What would it measure? there are multiple goals, e.g. throughput/MMU/pause time | <ul><li> What would it measure? there are multiple goals, e.g. throughput/MMU/pause time | ||
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</li></ul> | </li></ul> | ||
</li></ul> | </li></ul> | ||
== Risks == | |||
<ul> | <ul> | ||
<li> Team is responsible for many top crashers</li> | <li> Team is responsible for many top crashers</li> | ||
Revision as of 00:58, 14 August 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
Original schedule
| Milestone | Task | Deliverable | Assigned | Estimated Weeks | Expected Date | Actual Date |
|---|---|---|---|---|---|---|
| 1 | Rooting analysis in the shell (x64) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger | 2 | 3/7/2013 | 3/2/2013 |
| 2 | Rooting analysis in the shell (arm) | green on mozilla-inbound | sfink | 2 | pending | |
| 3 | Exactly rooted shell (x64) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger | 2 | 3/14/2013 | done? |
| 4 | Exactly rooted shell (arm) | green on mozilla-inbound | sfink | 2 | pending | |
| 4.1 | Exactly rooted js/src | green on mozilla-inbound | jonco | 3 | 5/9/2013 | in progress |
| 5 | GGC no-jit shell only build on TBPL (x64) | green on mozilla-inbound | terrence | 6 | 2/21/2013 | 4/7/2013 |
| 6 | GGC no-jit shell only build on TBPL (arm) | green on mozilla-inbound | sfink, terrence | 2 | pending | |
| 7 | JIT support (x64) (Bug 706885) | TBPL build using JITs and Ion+Baseline+GGC displayed on AWFY | bhacket | 8 | 3/15/2013 | 4/7/2013 |
| 8 | JIT support (arm) | TBPL build using JITs and Ion+Baseline+GGC displayed on AWFY | bhacket | 2 | pending | |
| 9 | Optimized GGC in shell (x64 + arm) | Ion+GGC faster than Ion-GGC on AWFY | bhacket | 12 | 6/1/2013 | not started |
| 10 | Static rooting analysis - browser | available via mrgiggles and URL | sfink, bhacket | 12 | 6/1/2013 | done |
| 10.1 | Static analysis on TBPL - browser | visible on tbpl | sfink | not started | ||
| 10.2 | Static rooting analysis - b2g | available via mrgiggles and URL | sfink | pending | ||
| 10.3 | Static analysis on TBPL - b2g | visible on tbpl | sfink | not started | ||
| 11 | Exactly rooted browser (x64 + arm) | green on mozilla-inbound | sfink, jonco, evilpie, Ms2ger, terrence | 16 | 7/1/2013 | in progress |
| 12 | GGC in the browser (x64 + arm) | green on AWFY | terrence | 16 | 10/1/2013 | not started |
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