530641 - Workers: Should respect JS JIT pref

Status: RESOLVED WORKSFORME

(Core :: DOM: Core & HTML, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Mr. bent tells me that currently they don't.

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Attachment: Make Workers listen for changes to jit.content

This patch was pretty easy ... perhaps too easy.  I hope I didn't violate any threadsafety rules, please check carefully!

I tested it by flipping the pref during long worker computations, and it didn't seem to break anything.  (And wow, the JIT makes a huge difference for bz's mandelbrot demo.)  Interestingly enough, the JIT-enabledness state change seemed to be applied nearly instantaneously while the workers were still executing.  Kudos to the spidermonkey guys for getting that to work.

One issue is that this patch sets JIT-enabledness for all Worker JSContexts based on jit.content; it doesn't attempt to determine whether chrome or content JS is executing on the JSContext, and so ignores jit.chrome.  Is that going to be an issue?  Does browser.js use workers at all?

Comment 2

[Alon Zakai (:azakai)]

This would be very useful to have (could have used it in bug 653967 right now, for example).

Did this get forgotten, or have we given up on it?

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

This was a four-day project and I just ran out of time.  I'd still like to take this patch if it wasn't fixed in the meantime.

Comment 4

[Alon Zakai (:azakai)]

This hasn't been fixed in the meantime, and would be useful to have I think.

Comment 5

[Jan de Mooij [:jandem]]

We need this to enable TI for web workers. We can't hard code it since TI will be disabled by default when it lands on TM.

Chris, still interested in finishing this patch?

Comment 6

[Ben Turner (not reading bugmail, use the needinfo flag!)]

All this code is gone soon, we'll need a different approach as soon as bug 649537 lands.

Comment 7

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Will be fixed in bug 649537.