[erlang-questions] Chameneos.rednux micro benchmark
Fri Oct 10 22:47:20 CEST 2008
On Oct 10, 2008, at 12:54 PM, Greg Burri wrote:
> I'm very surprise to see the differences between these two same
> benchmarks on shootout.alioth.debian.org :
> 1) Quad core : http://shootout.alioth.debian.org/u64q/benchmark.php?test=chameneosredux&lang=hipe
> 2) Mono core : http://shootout.alioth.debian.org/u64/benchmark.php?test=chameneosredux&lang=hipe
> Here are the CPU times :
> 1) 2095.18 s
> 2) 37.03 s
> I try on my machine with a) "-smp enable" and b) "-smp disable" :
> a) 47.863 s
> b) 18.285
> Maybe It's not strange to see a such difference because of inter-cpu
> message passing. But the difference on shootout.alioth.debian.org is
> too large
> What should we do ?
Are you using HiPE? There's some chance that could explain some of
the relative difference.
I don't think message passing is the issue. I suspect it's lack of
process affinity. The chameneos processes are likely getting bounced
around between schedulers constantly.
In the short term, I'm not sure what can be done other than requesting
the benchmark be run with '-S 1', which really kinda defeats the
purpose. It would be nice to have a different solution, as I agree
that this situation is pretty embarrassing. This task is such a
natural for the actor-model and Erlang; it's a shame the performance
ends up being so poor.
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