Bug 118401 – fourthTier: FTL should better report its compile-times and it should be able to run in a mode where it doesn't spend time generating OSR exits

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

[Filip Pizlo]

My current suspicion is that most of the time is spent in OSR exit computation.  We know we can do better there, so it would be useful to be able to confirm this hypothesis on a variety of benchmarks.

[Filip Pizlo]

Created attachment 206109 [details]
the patch

[Filip Pizlo]

Landed in http://trac.webkit.org/changeset/152432

[Geoffrey Garen]

> My current suspicion is that most of the time is spent in OSR exit computation.

Did this turn out to be true?

[Filip Pizlo]

(In reply to comment #3)
> > My current suspicion is that most of the time is spent in OSR exit computation.
> 
> Did this turn out to be true?

Currently LLVM compile times reduce by 30% if it doesn't have to deal with OSR exit marshaling.  So, no, it's not "most" of the time, right now.

But if you consider that we're also spending some significant fraction of time setting up pass managers, contexts, modules, execution engines, etc., I suspect that it'll be more than 30% if those other issues are fixed.