On Fri, Mar 13, 2015 at 6:14 PM, Malek Musleh <malek.mus...@gmail.com> wrote: > Hi, > > I am trying to get a better understanding of when the OSR optimization > is invoked. As per my understanding, CrankShaft is only invoked for > functions which have been seen at least 2, based on the parameter > kProfilerTicksBeforeOptimization = 2 in runtime-profiler.cc. But > because there might be functions that get invoked only once, because > they may be "long running", there is opportunity for optimizing the > long running function via on stack replacement. > > My specific question is how does the runtime profiler determine if the > function in question is "long enough" to attempt OSR? I can see OSR is > not attempted if there are too many formal parameters, but not where > it is decided that it passes the checks? > > > Malek
If I understand your question right: V8 inserts checks in function prologs and around loop edges where it calls into the run-time.[0] If the run-time sees the same JS function at the top of the stack several times in a row, and if that function meets all criteria, it will optimize it. Hope that helps. Let me know if I need to go into more detail. [0] That's the "call StackCheck" and "call InterruptCheck" instructions you see in the generated machine code. The stack check doubles as an interrupt check. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
