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From "Mikhail Fursov" <mike.fur...@gmail.com>
Subject Re: [DRLVM][GC] (HARMONY-2398) patch for GCv5 alloc helper inlining
Date Thu, 07 Dec 2006 14:38:22 GMT
Rana,
Allocation helper inlining is turned on only in server mode (-Xem:server)
and only for gc_cc
Even running in server mode there is a nuance: we do not have OSR so let the
method to be recompiled before testing.
I can help you to prepare configuration for -Xem:opt mode and rerun the
test. I think we will be as fast as SUN on windows, where FS[14] is used but
not system call to access TLS. The problem with TLS system call is quite
simple: we do not move it out from loop today.

On 12/7/06, Rana Dasgupta <rdasgupt@gmail.com> wrote:
>
> Since the allocation helper is inlined now, I reran the old allocation
> rate test( with the default heapsize 256 M ) ...while gc_gen and gc_cc are
> in the same ballpark, there is still some way to go to catch up with RI. Log
> attached.
>
>
>
>
> On 12/5/06, Mikhail Fursov <mike.fursov@gmail.com> wrote:
> >
> > If you compare performance of allocation - allocation fast path helper
> > code
> > is all you need.
> > And we need to check performance not with microtests, but use real
> > benchmarks. Microtests can hide cache misses in our example.
> >
> > On 12/5/06, Ivan Volosyuk <ivan.volosyuk@gmail.com> wrote:
> > >
> > > Helper code is equal. GC code is not. Lets compare apples with
> > oranges.
> > > --
> > > Ivan
> > >
> > > On 12/5/06, Mikhail Fursov <mike.fursov@gmail.com> wrote:
> > > > The helpers code is equal, except this load. So if we have different
> >
> > > > performance -> this extra memory access is the cause.
> > > >
> > > > On 12/5/06, Ivan Volosyuk <ivan.volosyuk@gmail.com> wrote:
> > > > >
> > > > > I think in order to do this comparison, other conditions should be
> > > > > equal. Comparing helper with 1 dependent load in gc_cc and helper
> > with
> > > > > 2 dependent loads in gc_v5 makes no sense to me.
> > >
> >
> >
> >
> > --
> > Mikhail Fursov
> >
> >
>
>


-- 
Mikhail Fursov

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