Author: Vincent Diepeveen
Date: 05:44:18 04/10/03
Go up one level in this thread
On April 09, 2003 at 17:58:21, Robert Hyatt wrote: as usual you were asleep when replying. i did math for a single cpu. that extrapolates to more cpu's as well. If you first slowdown crafty in order to then get a better speedup from SMT that's your choice. >On April 09, 2003 at 17:02:34, Vincent Diepeveen wrote: > >>On April 09, 2003 at 11:52:48, Charles Worthington wrote: >> >>it shows that SMT is still in its childhood with the current P4s. Getting a % or >>10 in nps speed from hyperthreading is not enough to get a positive speedup. >> >>Consider this. >> >>suppose fritz gets 1.7 speedup out of 2 processors. >>suppose hyperthreading speeds up 10%. >> >>Then what is actual speedup? >> 1.0 * 1.10 (speedup) * (1.7 / 2.0) = 0.935 which is SLOWER than 1.0 without. >> >>Easy math. >> > >Poor math. If it gets 1.7 out of a dual, and the single cpu version does 1M >nodes per >second, and hyper-threading brings that to 1.3M, then the effective speedup will >.7 of >that extra 30% which turns into 1.21 X faster in terms of time to solution. >That does >assume that SMT makes his raw speed 1.3X faster, and that with two equal >processors >his speedup is 1.7. > >Your math is bad. > > >>>I ran the Deepfritzmark and Shreddermark tests with hyperthreading disabled then >>>enabled with some very confusing results that I am hoping someone can help >>>explain: >>> >>>Test set #1 Hyperthreading Disabled, 64MB Hash, Engine Parameters @ default >>> >>>Shredder 7.04: Shreddermark: 2227 +- 0 (1.5s) 705kN/s >>> >>>Deep Fritz 7 : Deepfritzmark: 2724 +- 44 (3.1s) 2252kN/s >>> >>> >>> >>> >>>Test set #2 Hyperthreading Enabled, 64MB Hash, Engine Parameters @ Default >>> >>>Shredder 7.04: Shreddermark: 2227 +- 0 (1.5s) 803kN/s >>> >>>Deep Fritz 7 : Deepfritzmark: 2476 +- 0 (3.2s) 2555kN/s >>> >>> >>> >>>Test set #3: Hyperthreading Enabled, 32 MB Hash, Engine Parameters @ Default >>> >>>Shredder 7.04: Shreddermark: 2784 +- 0 (0.4s) 907kN/s >>> >>>Deep Fritz 7: Deepfritzmark: 2476 +- 0 (3.4s) 2532kN/s >>> >>> >>> >>>Test set #4; Hyperthreading enabled, 16MB Hash, engine parameters @ default >>> >>>Shredder 7.04; Shreddermark: 2784 +- 0 (0.4s) 1008kN/s >>> >>>Deep fritz 7: Deepfritzmark: 2476 +- 0 (4.5s) 2544 kN/s >>> >>> >>> >>>This is somewhat confusing as Fritz scored the highest fritzmark with >>>hyperthreading_disabled_ even though his kN/s were_far_lower. Shredder scored >>>far better with it_enabled_ both in result, speed, and time to solution. >>>Also Shredder seemed to benefit more from the smaller hash sizes where Fritz >>>seemed relatively worsened by them. Does anyone have any insight as to these >>>seemingly contradictory results? And would I be better to run Deep Fritz with >>>the hyperthreading diasabled even though his kN/s is considerably lower? >>> >>>Charles
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