863795 - Remove duplicates from the store buffer when compacting

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Terrence Cole [:terrence]]

Attachment: v0

Brian's research in Bug 851057 found that removing duplicates before marking improved the performance of the object buffer. This patch implements this logic on the base store buffer class and performs this pass for all store buffers.

In practice, we will probably want to specialize |compact()| for each edge type and only run the compaction algorithms that are most relevant for each type. Alternatively, we may want to remove the current notInSet compaction by simply checking this condition at every store buffer insertion. These will require profiling, so I am leaving them for a separate pass.

Comment 1

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Comment on attachment 739682 [details] [diff] [review]
v0

Review of attachment 739682 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/gc/StoreBuffer.cpp
@@ +101,5 @@
>  template <typename T>
>  void
> +StoreBuffer::MonoTypeBuffer<T>::compactRemoveDuplicates()
> +{
> +    JS_ASSERT(duplicates.count() == 0);

duplicates.empty()

Comment 2

[Terrence Cole [:terrence]]

Green try run at:
https://tbpl.mozilla.org/?tree=Try&rev=0ccf9f11d4d9

Pushed at:
https://hg.mozilla.org/integration/mozilla-inbound/rev/36ed827e43af

Comment 3

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/36ed827e43af