Author: Eugene Nalimov
Date: 09:54:30 11/19/03
Go up one level in this thread
On November 19, 2003 at 12:15:23, Robert Hyatt wrote: >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". Use Windows :-) I believe we resolved majority of issues (though yes, Windows NUMA API is minimalist and sometimes ugly). If you'll hit some non-driver-related problems AMD or NT people will help you :-) Thanks, Eugene
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