Author: Aaron Gordon
Date: 18:47:22 05/25/03
Go up one level in this thread
On May 25, 2003 at 15:08:39, Matthew White wrote: >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 Cool, thats what I was expecting. Looks like you get a 53% increase out of OGR. Wonder whats up with RC5...
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