Author: Matthew White
Date: 12:08:39 05/25/03
Go up one level in this thread
On May 25, 2003 at 09:23:42, Aaron Gordon wrote: >On May 24, 2003 at 16:53:57, Matthew White wrote: > >>On May 23, 2003 at 23:40:23, Aaron Gordon wrote: >> >>>>What are they measuring? >>>> >>>>IE running two copies _should_ see each copy run about 1/2 as fast with SMT >>>>on, since each copy is getting roughly 50% of available cpu core resources >>>>when running the same instruction streams. >>>> >>>>Or do you mean something else? >>> >>>It's keys per second for RC5, nodes per second for OGR. What I mean is it spawns >>>1 thread per processor (or virtual processor in HT's case). >>>My Dual Celeron 400MHz box gets an exact 2.00x speedup with this, I'm assuming >>>because it doesn't hit the main memory at all. Any other dual processor system >>>should also get a 2.00x speedup as well.. however I saw some results that were >>>puzzling. Here they are... >>> >>>Dual Xeon (P4) 2.0GHz without HT - 2.8 million keys/sec per thread (5.6mk/s >>>total), 2 threads total. >>> >>>Dual Xeon (P4) 2.0GHz with HT enabled - 0.72 million keys/sec per thread >>>(2.88mk/s total), 4 threads total. >>> >>>I was just wondering if you could run the same tests and confirm this. I would >>>have figured RC5/OGR would have managed a nice boost from HT, so it's surprising >>>to me. >>I have seen similarly poor performance on my Dual Xeon 2.4 GHz with HT enabled. >>I manually configured the client to only spawn 2 threads. >> >>Matt > >Did you try OGR too or did you only experience the extreme slowdown with HT >enabled only with RC5? If OGR was affected in any way, what was the speed >increase/decrease? Thanks I just reran the test. With 2 threads, I got 8.6M nodes/sec/thread on OGR and 2.6M keys/sec/thread on RC5-72. With 4 threads, I got 6.6M nodes/sec/thread OGR and 1.1M keys/sec/thread on RC5-72. So, OGR does show increased performance with HT, but RC5-72 does not. I only run RC5 cracking, though, since I am much more interested in cryptography than the Optimal Goloumb Rulers problem :). Regards, Matt
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