Wow, thats awesome information. That would explain why the function in
question is slow, and why inlining a couple of the function calls it makes
decreases overall speed.
How do I read the trace I get back? I'm getting this:
**** DEOPT: Arbiter.applyImpulse at bailout #49, address 0x0, frame size 264
[deoptimizing: begin 0x1b70ac6a67f1 Arbiter.applyImpulse @49]
translating Arbiter.applyImpulse => node=432, height=216
0x7fff6f711630: [top + 248] <- 0x3ebe7f33eb9 ; [esp + 296]
0x3ebe7f33eb9 <JS Object>
0x7fff6f711628: [top + 240] <- 0x2457afa6b4ad ; caller's pc
0x7fff6f711620: [top + 232] <- 0x7fff6f7116c0 ; caller's fp
....
I assume address 0x0 means something the function is doing is hitting a
null object. Does bailout #49 mean anything? The function is (later)
repeatedly optimized and deoptimized again with bailout #8. How do I track
these down?
-J
On Monday, 26 December 2011 23:56:31 UTC+11, Vyacheslav Egorov wrote:
>
> This is a multiplication stub that is usually called from non-optimized
> code (or optimized code that could not be appropriately specialized).
> Non-optimizing compiler does not try to infer appropriate representation
> for local variable so floating point numbers always get boxed.
>
> If this stub is high on the profile then it usually means that optimizing
> compiler either failed to optimize hot function which does a lot of
> multiplications or it failed to infer an optimal representation for some
> reason.
>
> Bottom up profile should show which functions invoke the stub. Then you
> should inspect --trace-opt --trace-bailout --trace-deopt output to figure
> out what optimizer does with those function.
>
> --
> Vyacheslav Egorov
>
> On Mon, Dec 26, 2011 at 7:00 AM, Joseph Gentle <[email protected]> wrote:
>
>> What does it mean when I see BinaryOpStub_MUL_Alloc_HeapNumbers in my
>> profile? Does that mean the compiler is putting local number variables on
>> the heap? Why would it do that?
>>
>> -J
>>
>> --
>> v8-users mailing list
>> [email protected]
>> http://groups.google.com/group/v8-users
>
>
>
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