Author: Vincent Diepeveen
Date: 14:02:34 04/09/03
Go up one level in this thread
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. >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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