Javascript:SpiderMonkey:ProjectGenerationGarbageCollection: Difference between revisions

<p>Wiki conversion of original Google Document: https://docs.google.com/a/jamsni.com/document/d/1-GZ8F0ZabvdpCnRQaecId0yuu4QFYr5pAvnRC_KFchc/edit

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<p>Implement Generational Garbage collection in Spider Monkey. &lt;Some goal based off V8 performance delta&#160;% on Earley Boyer benchmark&gt;</p>

<b>Accountable</b>: Naveed<br />

<br/>

<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>

<p>12 weeks started

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<ul><li> Get jit-tests green <span class="fck_mw_template"><span class="fck_mw_template">{{bug|745742}}</span></span>

</li><li> Get js ref tests green  

<ul><li> Fix all discovered rooting hazards (~800) (sfink,jonco) - 4 weeks

</li><li> Optimize all discovered over-rooting (~100)

</li></ul>

</li></ul>

<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> Baseline JIT <span class="fck_mw_template"><span class="fck_mw_template">{{bug|831507}}</span></span> - &lt;ask jandem/djvj for an estimate&gt;

</li></ul>

<ul><li> Implement prototype algorithm (terrence) - 1 week

</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

</li></ul>

</li></ul>

<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>

<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.

<ul><li> Also v8 deltablue, raytrace

</li></ul>

</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>

<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> Make JS_IsAboutToBeFinalized indirect <span class="fck_mw_template"><span class="fck_mw_template">{{bug|765432}}</span></span> - 10 weeks

</li></ul>

<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

</li></ul>

</li></ul>

<ul>

<li> Team is responsible for many top crashers</li>

<li> GGC algorithm has not been decided on - it may not be faster</li>

<li> JSD1 exact rooting is lurking</li>

</ul>