<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Oct 10, 2008, at 12:54 PM, Greg Burri wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">Hi,<br>I'm very surprise to see the differences between these two same benchmarks on <a href="http://shootout.alioth.debian.org">shootout.alioth.debian.org</a> :<br>1) Quad core : <a href="http://shootout.alioth.debian.org/u64q/benchmark.php?test=chameneosredux&lang=hipe">http://shootout.alioth.debian.org/u64q/benchmark.php?test=chameneosredux&lang=hipe</a><br> 2) Mono core : <a href="http://shootout.alioth.debian.org/u64/benchmark.php?test=chameneosredux&lang=hipe">http://shootout.alioth.debian.org/u64/benchmark.php?test=chameneosredux&lang=hipe</a><br><br>Here are the CPU times :<br> 1) 2095.18 s<br>2) 37.03 s<br><br>I try on my machine[1] with a) "-smp enable" and b) "-smp disable" :<br>a) 47.863 s<br>b) 18.285<br><br>Maybe It's not strange to see a such difference because of inter-cpu message passing. But the difference on <a href="http://shootout.alioth.debian.org">shootout.alioth.debian.org</a> is too large<br> What should we do ?<br></div></blockquote></div><br><div>Are you using HiPE? There's some chance that could explain some of the relative difference.</div><div><br></div><div>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.</div><div><br></div><div>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.</div><div><br></div><div>-k</div></body></html>