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From Egor Pasko <egor.pa...@gmail.com>
Subject Re: [drlvm][jit] replay compilation methodology
Date Mon, 28 Apr 2008 12:41:06 GMT
On the 0x431 day of Apache Harmony Naveen Neelakantam wrote:
> On Apr 25, 2008, at 10:32 AM, Egor Pasko wrote:
> 
> > On the 0x431 day of Apache Harmony Naveen Neelakantam wrote:
> >> On Apr 25, 2008, at 8:35 AM, Egor Pasko wrote:
> >>
> >>>> The problem is that a staged optimizing-compiler (e.g.
> >>>> server.emconf)
> >>>> can make it difficult to isolate the performance effects of a
> >>>> particular compiler optimization or GC algorithm because the
> >>>> compiler
> >>>> runs concurrently with the application/GC.
> >>>>
> >>>> A reasonable solution to this problem is the following:
> >>>> 1) Run the application with the staged compiler enabled and
> >>>> collect a
> >>>> log of its actions.
> >>>> 2) When measuring performance, run the application twice in a row,
> >>>> within the same JVM instance.  During the first run the JVM
> >>>> consumes
> >>>> the log produced in (1) and uses it to optimize the code exactly
> >>>> the
> >>>> same as in (1).  During the second run the compiler is disabled and
> >>>> measurements are made.
> >>>
> >>> then just dump profile at EdgeProfilerAnnotationPass and then reload
> >>> in (2). Should solve the problem, IMHO.
> >>
> >> Really?  That seems insufficient because of value-profile-based
> >> devirtualization.  The edge profile is only part of the story right?
> >
> > Oh, I forgot. Nice catch! same in GuardedDevirtualizationPass.
> 
> Phew.  Ok, that's what I'm currently implementing.  I'll report back
> when I have something to share (hopefully a success story).

:) cool

-- 
Egor Pasko


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