Author: Anthony Cozzie
Date: 11:19:33 04/09/03
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On April 09, 2003 at 11:52:48, Charles Worthington wrote: >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 Remember that hyperthreading increases the SMP-ness of a program. Example: suppose hyperthreading increases your NPS by 10%. This means that instead of 1 processor with speed 1.0, you have two processors with speed .55. Now, according to Bob's rule of thumb, your speed is .55 + (.7*.55) = .935 (<1). In other words, due to the inefficiencies of searching in parallel, your time to solution went up even when your NPS went down. When Zappa searches without hash tables, its NPS goes up quite a bit. Among other things, a smaller hash table results in inferior move ordering. anthony
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