Author: Gerd Isenberg
Date: 14:04:11 11/06/03
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On November 06, 2003 at 15:55:10, Russell Reagan wrote: >In this thread: > >http://www.chess-archive.com/ccc.php?art_id=310212 > >Gian-Carlo Pascutto reported that his program, Deep Sjeng (compiled for 64-bit >hardware), ran 70% faster on an Opteron, clock for clock. As far as I know, Deep >Sjeng is not bitboard based. > >In this thread: > >http://www.talkchess.com/forums/1/message.html?325912 > >Eugene Nalimov reports that Crafy (compiled for 64-bit hardware) gets 1,761,569 >nps on a 1.8GHz Opteron. On my 2GHz Athlon, Crafty gets 1,230,931 nps. > >(2.0 / 1.8) x 1,761,569 = about 1,957,298 nps on a 2GHz Opteron > >So, clock for clock, Crafty is 1,957,298 / 1,230,931 = 1.59 times faster (60%) >on an Opteron, while Deep Sjeng was 70% faster. I suspect Eugene was using his >magic unreleased compiler also, which probably produces faster executables than >gcc. But that is speculation. > >So either Deep Sjeng is bitboard based, or the expected advantage that bitboard >engines were going to get that non-bitboard engines were not going to get does >not exist. Or I'm overlooking something else. > >Thoughts? hmm, a few aspects: are the Athlons you compare really equal? Let's see how other programs will perform. Sjeng may profit more from opteron features independent from 64-bit stuff, e.g. bigger cache, more registers and therefore less store/loads of locals and function parameters, faster memory and smarter branch prediction. And 64-bit bsf is still expensive vector path instruction with 9 cycles latency where all other pipes are blocked. Gerd
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