Author: Robert Hyatt
Date: 08:07:06 04/10/03
Go up one level in this thread
On April 10, 2003 at 08:44:18, Vincent Diepeveen wrote: >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. I did math that extrapolates to _everything_. If I get 1.7X speedup for two cpus, I will get _some_ speedup no matter how slow the second processor is. Which was my point. > >If you first slowdown crafty in order to then get a better speedup from SMT >that's your choice. I didn't "first slowdown crafty". The SMP version runs just as fast as the non-SMP version, so I have no idea what you are talking about... > >>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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