llvm dev - Dec 2009 - [LLVMdev] Help adding the Bullet physics sdk benchmark to the LLVM test suite?

Hi,

We are developing the open source Bullet physics engine, used by game and
movie studios,
and compiler performance tuning is important to us. See
http://bullet.googlecode.com
The physics engine includes collision detection, rigid body dynamics and
soft body dynamics.

I've been following the LLVM project for a while, and it seems the Clang C++
compiler is mature enough
to compile our source tree and benchmarks. Bullet 2.75 uses a lot of
SIMD-friendly vector operations,
that might be an interesting addition to the LLVM test suite.

We have cmake and autoconf/automake build system support, and the latest
benchmark is just a console application.
The SDK is under Bullet/src and the benchmarks Bullet/Demos/Benchmarks

I'm not very familiar with the LLVM test-suite. Is someone interested to
help integrating Bullet in the test suite?
Thanks a lot,
Erwin
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Hello, Erwin
> The physics engine includes collision detection, rigid body dynamics and
> soft body dynamics.
This sounds really promising addition to LLVM testsuite!
> to compile our source tree and benchmarks. Bullet 2.75 uses a lot of
> SIMD-friendly vector operations,
Which archs are currently supported for SIMD operations?
> The SDK is under Bullet/src and the benchmarks Bullet/Demos/Benchmarks
> I'm not very familiar with the LLVM test-suite. Is someone interested
to
> help integrating Bullet in the test suite?
Yes, I am. Should I just use the 2.75 release?
Anything special I should be aware of (e.g. special "benchmark" mode,
or "small" mode for embedded systems) ?

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

Hi Anton,

Thanks a lot for offering help.

Bullet uses basic linear algebra with 4-way vectors, quaternion and
matrices.
Although most of this is plain portable C++ perhaps LLVM can auto-vectorize
some of this?

There is a little bit of hand optimized x86 SSE code. This is only enabled
on 32bit Windows and Mac OSX Intel builds.
>> Should I just use the 2.75 release?
If you are interested, I think it is best to start with Bullet 2.75.
If it turns out that LLVM requires some modifications (due to current C++
limitations),
we can modify Bullet and go for an uncoming release such as Bullet 2.76
(planned around January 2010).

There is also ongoing work, together with AMD, to add OpenCL optimizations
for Bullet 3.x,
but that is not available yet in the short term.

>> Anything special I should be aware of (e.g. special
"benchmark" mode,
If you compile the Bullet SDK using one of the included build systems, such
as cmake or autotools,
it will try to compile all of the demos, many of them are using OpenGL/glut
graphics,
and a lot of optional 'extras'. I suggest removing all of that
(Bullet/Extras folder etc).
We modified the Bullet/Demos/Benchmarks so it runs as a console program,
without graphics by default.

You could take Bullet/Demos/Benchmarks as a starting point, and modify it so
it fits the LLVM test suite?

What hardware/platforms does the LLVM test suite run on typically?
Thanks,
Erwin



2009/12/15 Anton Korobeynikov <anton at korobeynikov.info>
> Hello, Erwin
>
> > The physics engine includes collision detection, rigid body dynamics
and
> > soft body dynamics.
> This sounds really promising addition to LLVM testsuite!
>
> > to compile our source tree and benchmarks. Bullet 2.75 uses a lot of
> > SIMD-friendly vector operations,
> Which archs are currently supported for SIMD operations?
>
> > The SDK is under Bullet/src and the benchmarks Bullet/Demos/Benchmarks
> > I'm not very familiar with the LLVM test-suite. Is someone
interested to
> > help integrating Bullet in the test suite?
> Yes, I am. Should I just use the 2.75 release?
> Anything special I should be aware of (e.g. special "benchmark"
mode,
> or "small" mode for embedded systems) ?
>
> --
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State University
>
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