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Re: octave and LLVM google summer of code project
From: |
Eugene I |
Subject: |
Re: octave and LLVM google summer of code project |
Date: |
Mon, 21 Apr 2008 23:46:36 -0700 (PDT) |
John W. Eaton wrote:
>
> For the above function, how does performance compare to
>
>
> I'm not saying that the JIT compiler it isn't useful, or even that my
> semi-vectorized solution is great (it is not really easy to read), I'm
> just curious about the difference.
>
Under opensuse 10.3 (running in a virtual machine - bad setup for
benchmarking so treat the timing results as order of magnitude estimates)
Original code:
Octave 3.0 (from suse build service) ~2.3 sec
FreeMat interpreter ~2.7 sec
FreeMat jit compiled (including compile time) ~ 0.02 sec
Vectorized code under FreeMat less than 0.005 sec.
No surprises here.
> Just when the array indices are scalars or any values? If they are
> any values, doesn't that mean relying on some library code to do the
> indexing? In Octave, that code is fairly complicated to handle
> logical indexing, array indexing, indexing when there are more or
> fewer indices than array dimensions, etc.
>
For now just when array indices are scalars. We can speedup other
expressions later on.
> I assume we are talking about the LLVM JIT compiler. Looking at the
> LLVM web page, the JIT compiler apparently supports X86, X86-64,
> PowerPC and PowerPC-64 systems. This may be the majority of systems
> today, but what about other systems? For example users of Octave on
> SPARC or Itanium systems might want to see the improved performance as
> well (I'm not saying that it is not worth doing even if only a limited
> number of systems are supported, just that there may be some
> limitations).
>
As I understand the plan is that LLVM is to become part of gcc suite as part
of link-time optimization implementation. So, I hope that support for more
cpus is coming. We looked at other options (Java JIT, Mono JIT, libjit) but
LLVM was by far the best one.
--
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- Re: octave and LLVM google summer of code project, (continued)
- Re: octave and LLVM google summer of code project, Eugene I, 2008/04/19
- Re: octave and LLVM google summer of code project, dbateman, 2008/04/19
- Re: octave and LLVM google summer of code project, Eugene I, 2008/04/19
- Re: octave and LLVM google summer of code project, dbateman, 2008/04/20
- Re: octave and LLVM google summer of code project, John W. Eaton, 2008/04/20
- Re: octave and LLVM google summer of code project, John W. Eaton, 2008/04/20
- Re: octave and LLVM google summer of code project, Eugene I, 2008/04/20
- Re: octave and LLVM google summer of code project, John W. Eaton, 2008/04/20
- Re: octave and LLVM google summer of code project, Eugene I, 2008/04/20
- Re: octave and LLVM google summer of code project, John W. Eaton, 2008/04/20
- Re: octave and LLVM google summer of code project,
Eugene I <=
Re: octave and LLVM google summer of code project, Wolfgang_M, 2008/04/15