Javascript:SpiderMonkey:ProjectGenerationGarbageCollection: Difference between revisions
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<h2> Objective </h2> | |||
Implement Generational Garbage collection in Spider Monkey. | <p>Implement Generational Garbage collection in Spider Monkey. <Some goal based off V8 performance delta % on Earley Boyer benchmark> | ||
</p> | |||
<ul><li> Accountable: Naveed | |||
</li></ul> | |||
<ul><li> Responsible: Terrence, Steve, Jon, Nicholas, and evilpie Ms2ger | |||
</li></ul> | |||
<ul><li> Consulted: bhackett billm | |||
</li></ul> | |||
<ul><li> Informed: Product Marketing | |||
</li></ul> | |||
Generational GC - | <p>Generational GC - <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=619558">Bug 619558</a> | ||
</p> | |||
<h2> Steps </h2> | <h2> Steps </h2> | ||
< | <p>Exact Rooting done in JS Shell <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=753203">Bug 753203</a> - 12 weeks started | ||
</p><p>Rooting Analysis on TinderBox (sfink) - 3 weeks | </p><p>Rooting Analysis on TinderBox (sfink) - 3 weeks | ||
</p><p>patch is ready for review, would fix the problem with some pushes not getting builds | </p><p>patch is ready for review, would fix the problem with some pushes not getting builds | ||
| Line 35: | Line 20: | ||
</p><p>Unhide it for inbound - keep it green | </p><p>Unhide it for inbound - keep it green | ||
</p><p>Get the root analysis build green - two weeks? | </p><p>Get the root analysis build green - two weeks? | ||
</p><p>Get jit-tests green | </p><p>Get jit-tests green <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=745742">Bug 745742</a> - 2 days | ||
</p><p>Get js ref tests green | </p><p>Get js ref tests green | ||
</p><p>Get jsapi-tests green | </p><p>Get jsapi-tests green <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831376">Bug 831376</a> | ||
</p><p>Fuzzer coverage of code | </p><p>Fuzzer coverage of code <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=773746">Bug 773746</a> | ||
</p><p>rely on static analysis to make this not be a whack-a-mole game | </p><p>rely on static analysis to make this not be a whack-a-mole game | ||
</p><p>Remove E4X | </p><p>Remove E4X | ||
| Line 44: | Line 29: | ||
</p><p>Add exact roots to stack structures - 2 weeks | </p><p>Add exact roots to stack structures - 2 weeks | ||
</p><p>AddRoot/RemoveRoot for Heap structures - 4 weeks | </p><p>AddRoot/RemoveRoot for Heap structures - 4 weeks | ||
</p><p>Static code analysis | </p><p>Static code analysis <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831409">Bug 831409</a> | ||
</p><p>Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks | </p><p>Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks | ||
</p><p>Optimize all discovered over-rooting (~100) | </p><p>Optimize all discovered over-rooting (~100) | ||
| Line 52: | Line 37: | ||
</p><p>http://people.mozilla.org/~bhackett/gcFunctions.html | </p><p>http://people.mozilla.org/~bhackett/gcFunctions.html | ||
</p><p><br /> | </p><p><br /> | ||
JIT Integration with post barriers - 4 weeks, parallelized | |||
</p><p>IonMonkey <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831506">Bug 831506</a> - 1 week (bhackett) | |||
</p><p>IonMonkey | </p><p>JaegerMonkey <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=764876">Bug 764876</a> - 2 days (bhackett) | ||
</p><p>JaegerMonkey | </p><p>Baseline JIT <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831507">Bug 831507</a> - <ask jandem/djvj for an estimate> | ||
</p><p>Baseline JIT | |||
</p><p>Generation Garbage Collection in the Shell | </p><p>Generation Garbage Collection in the Shell | ||
</p><p>Implement prototype algorithm (terrence) - 1 week | </p><p>Implement prototype algorithm (terrence) - 1 week | ||
</p><p>This is a potential milestone: we would need to build it and test it on TBPL similar to how |r| works now -- |GGCJS|. | </p><p>This is a potential milestone: we would need to build it and test it on TBPL similar to how |r| works now -- |GGCJS|. | ||
</p><p>Exactly Root the Browser | </p><p>Exactly Root the Browser <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831379">Bug 831379</a> - 10 weeks | ||
</p><p>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. | </p><p>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. | ||
</p><p>Performance Tuning - 4 weeks (This should probably start asap) | </p><p>Performance Tuning - 4 weeks (This should probably start asap) | ||
</p><p>Test against V8 Earley-Boyer benchmark. | </p><p>Test against V8 Earley-Boyer benchmark. | ||
</p><p>Also v8 deltablue, raytrace | </p><p>Also v8 deltablue, raytrace | ||
</p><p>Implement a Nursery | </p><p>Implement a Nursery <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=706885">Bug 706885</a> - 1 week | ||
</p><p>We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf - 6 weeks | </p><p>We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf - 6 weeks | ||
</p><p>Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable - ??? weeks (start early) (bhackett) | </p><p>Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable - ??? weeks (start early) (bhackett) | ||
</p><p>Re-implement HashTable rekeying | </p><p>Re-implement HashTable rekeying | ||
</p><p>We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks | </p><p>We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks | ||
</p><p>Make the Post Barrier Verifier Green in the browser | </p><p>Make the Post Barrier Verifier Green in the browser <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=764882">Bug 764882</a> | ||
</p><p>Investigate how long it will take to do generational barriers - 1 week | </p><p>Investigate how long it will take to do generational barriers - 1 week | ||
</p><p>We may need to rewrite the maps in xpconnect and the browser in terms of HashTable: this could be a bunch of work. | </p><p>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 <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=765432">Bug 765432</a> - 10 weeks | |||
</p> | </p> | ||
</p> | <h2> Other </h2> | ||
<p>Should we establish a new benchmark specifically for GGC. (sfink votes yes) | |||
</p><p>What would it measure? there are multiple goals, e.g. throughput/MMU/pause time | |||
</p><p>Should we make it a public benchmark? | |||
Should we establish a new benchmark specifically for GGC. (sfink votes yes) | </p><p>What workloads should we consider? | ||
</p><p>compartmental GC very important to us, not necessarily applicable to other implementations | |||
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. | allocation rate (broken down into live vs garbage), steady behavior vs swapping between allocation + computation modes, etc. | ||
</p><p>How can we keep our advantage on Splay benchmark | |||
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 | 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 | ||
</p><p>Compacting GC - Revisit in Febuary/March - 1 Month | |||
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. | Delayed until exact rooting is fully done. We can add this in if we have time in the schedule that we cannot parallelize. | ||
</p> | |||
<h2> Risks </h2> | |||
<ul><li> Team is responsible for many top crashers | |||
</li></ul> | |||
<ul><li> External rooting API has not been designed | |||
</li></ul> | |||
<ul><li> GGC algorithm has not been decided on - it may not be faster | |||
</li></ul> | |||
<ul><li> JSD1 exact rooting is lurking | |||
</li></ul> | |||
Revision as of 18:22, 25 January 2013
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, and evilpie Ms2ger
- Consulted: bhackett billm
- Informed: Product Marketing
Generational GC - <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=619558">Bug 619558</a>
Steps
Exact Rooting done in JS Shell <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=753203">Bug 753203</a> - 12 weeks started
Rooting Analysis on TinderBox (sfink) - 3 weeks
patch is ready for review, would fix the problem with some pushes not getting builds
fix up other stuff broken by above change
patch would fix last remaining problem with getting it on Try server
Unhide it for inbound - keep it green
Get the root analysis build green - two weeks?
Get jit-tests green <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=745742">Bug 745742</a> - 2 days
Get js ref tests green
Get jsapi-tests green <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831376">Bug 831376</a>
Fuzzer coverage of code <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=773746">Bug 773746</a>
rely on static analysis to make this not be a whack-a-mole game
Remove E4X
Do something about JSD
Add exact roots to stack structures - 2 weeks
AddRoot/RemoveRoot for Heap structures - 4 weeks
Static code analysis <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831409">Bug 831409</a>
Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks
Optimize all discovered over-rooting (~100)
Automate static analysis (sfink)
Need a server (dm-sixgill01?)
http://people.mozilla.org/~bhackett/rootingHazards.html
http://people.mozilla.org/~bhackett/gcFunctions.html
JIT Integration with post barriers - 4 weeks, parallelized
IonMonkey <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831506">Bug 831506</a> - 1 week (bhackett)
JaegerMonkey <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=764876">Bug 764876</a> - 2 days (bhackett)
Baseline JIT <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831507">Bug 831507</a> - <ask jandem/djvj for an estimate>
Generation 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|.
Exactly Root the Browser <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=831379">Bug 831379</a> - 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)
Test against V8 Earley-Boyer benchmark.
Also v8 deltablue, raytrace
Implement a Nursery <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=706885">Bug 706885</a> - 1 week
We may need to Implement Bill’s Pools/Zones idea to get the nursery to the requisite perf - 6 weeks
Refactor code to avoid rooting on hot paths and keep rooter overhead acceptable - ??? weeks (start early) (bhackett)
Re-implement HashTable rekeying
We undid this code because it was a perf regression and was still a bit buggy. (terrence) - 3 weeks
Make the Post Barrier Verifier Green in the browser <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=764882">Bug 764882</a>
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 <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=765432">Bug 765432</a> - 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