Bug 13389 – [js-collector-tweaks] move mark and collectOnMainThreadOnly bits into separate bitmaps

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Maciej Stachowiak]

Move mark and collectOnMainThreadOnly bits into separate bitmaps. This saves 4 bytes per cell, allowing shrink of cell size to 32, which leads to a .8% speed improvement on iBench.

[Maciej Stachowiak]

Created attachment 14070 [details]
09-js-gc-mark-bitmap+32byte-cell.patch.txt

[Darin Adler]

Comment on attachment 14070 [details]
09-js-gc-mark-bitmap+32byte-cell.patch.txt

+#include <sys/mman.h>

I don't think it's right that have this outside an #if -- is it really a header that exists on all JavaScriptCore platforms.

Now that all these constants have to be moved into a header file, maybe we should make them have non-all-capitals name or use a namespace or something. They're pretty ugly.

[Maciej Stachowiak]

(In reply to comment #2)
> (From update of attachment 14070 [details] [edit])
> +#include <sys/mman.h>
> 
> I don't think it's right that have this outside an #if -- is it really a header
> that exists on all JavaScriptCore platforms.

OK, I'll put it in an ifdef (I think it is only needed for non-Darwin Unix platforms, to get mmap/munmap).

> Now that all these constants have to be moved into a header file, maybe we
> should make them have non-all-capitals name or use a namespace or something.
> They're pretty ugly.

I'm happy to give them more normal names, but maybe that should be a separate patch?

[Geoffrey Garen]

Code looks right to me, modulo darin's comments.

[Maciej Stachowiak]

Created attachment 14146 [details]
fix the sys/mman.h thing, plus some other cleanups

[Maciej Stachowiak]

Created attachment 14148 [details]
actually fixed the mman thing

[Darin Adler]

Comment on attachment 14148 [details]
actually fixed the mman thing

r=me