Author: Robert Hyatt
Date: 09:15:23 11/19/03
Go up one level in this thread
On November 18, 2003 at 16:06:43, Gian-Carlo Pascutto wrote: >On November 18, 2003 at 15:58:39, Russell Reagan wrote: > >>On November 18, 2003 at 15:22:51, Gian-Carlo Pascutto wrote: >> >>>Don't forget the Opteron is WAY faster running old 32 bit code too. You don't >>>need 64 bit applications to take advantage of them. >> >>I don't know about that. I've seen a lot of benchmarks where the Opteron just >>edges out the P4 (faster, but not WAY faster). I've also seen some where the P4 >>edges out the Opteron, but they are almost always in the same ballpark. >> >>The specint scores for a 2GHz Opteron and a 2GHz Athlon are not too far off >>either. The Opteron scores were about 18-20% faster than the equivalently >>clocked Athlon running Crafty, but the Opteron scores for 32-bit code were >>compiled with the latest Intel C++ compiler (7 something), while the only >Althon 2GHz scores they have were using Intel C++ 5 something. I suspect if >>both used the newer compiler, the difference would be less than 18%, which is >>not WAY faster. > >IIRC for Athlons the Intel compilers are equivalent (They're INTEL compilers >after all ;-) > >>How about Deep Sjeng? You posted your 64-bit numbers. Do you have any numbers >>that would compare an equivalently clocked Opteron and 32-bit Athlon both >>running 32-bit code? You still haven't told us if Deep Sjeng uses bitboards, >>which makes it difficult to extract meaning from your 64-bit numbers. A 70% >>speedup for a bitboard program is very nice, but a 70% speedup for a >>non-bitboard program would really say something, considering Crafty only gets >>about a 60% boost. > >Considering you know that Crafty is the archetypal bitboard program, >and that I haven't exactly kept my opinions about bitboards secret, >perhaps the answer to that question isn't _that_ hard to figure out. > >>That is something I've been very curious about lately, whether a chess program >>that doesn't use 64-bit values heavily (0x88, any array based program, etc.) >>will get much of a speed boost on the Opteron compared to the fastest 32-bit >>processors. Crafty is already faster than a lot of non-bitboard programs on >>32-bit hardware. If it gets a 60-70% boost, while others get a 10-20% boost, >>that's a significant blow to the non-bitboarders. > >I'll have more Opteron data 'soon'. > >But really, the chip is fast 32 bit and BLAZING 64 bit. I don't understand >why people still have questions. I don't. And I've noticed Bob and Eugene >don't have any more either these days ;) > >-- >GCP I _still_ have questions. The NUMA issues are non-trivial. Memory hot-spots kill performance. Etc. But I agree that done right, a program can really zip right along. After studying it quite a bit, I would not yet suggest Linux as the platform for a NUMA box, yet. I'm looking at it closely and may fool around with it some myself once we get an opteron in here, if the problems are not solved before then. The issues are "interesting" to say the least. The hash table is just _one_ example of what is "interesting".
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