Author: Aaron Gordon
Date: 19:41:08 11/11/03
Go up one level in this thread
On November 11, 2003 at 21:05:31, Eugene Nalimov wrote: >On November 11, 2003 at 19:55:22, Aaron Gordon wrote: > >>On November 11, 2003 at 17:38:38, Eugene Nalimov wrote: >> >>>On November 11, 2003 at 08:50:53, Aaron Gordon wrote: >>> >>>>It would be better had they used a quad or 8-way Opteron running 2GHz or more. >>>>From some testing I've done in the past you can figure a single Opteron 2GHz == >>>>a P4-3.6GHz in Fritz 8 (32bit mode). So, a Quad Opteron 2.0 == Quad P4-3.6. >>>>Almost 30% faster, plus the memory bandwidth available would probably push it a >>>>bit over that with large hash table sizes. 8-way Opteron 2.0 would of course be >>>>like 8 p4-3.6's (however with some 40gb/s+ memory bandwidth available depending >>>>on bus speed). >>>> >>>>Why not use the best hardware? Seems like if you'd want to promote your new >>>>'awesome' chess program you'd want to give it the best chance of winning. >>> >>>I am not so sure that for SMP program that is not NUMA-aware quad Opteron will >>>be faster than quad Xeon, even if single-CPU Opteron is faster than single-CPU >>>Xeon. >>> >>>At least it was so for Crafty. Before we modified it to be NUMA-aware, 1.8GHz >>>Opteron was faster than 1.5GHz Itanium, but quad 1.4GHz Itanium was faster than >>>quad 1.5GHz Opteron. Actually, Itanium was slightly faster even on 2 CPUs. >>> >>>Thanks, >>>Eugene >> >>Fritz doesn't run on the Itanium platform that I'm aware of.. not without >>emulation. All of the Itanium emulation I've seen runs like a 486.. so.. back to >>the 4 to 8-way Opteron arguement I go. :) > >I gave numbers for Crafty. Not for Fritz, Chess Tiger, Hiarcs, etc. I definitely >told so in my post. > >Ok, trying to re-phrase it: > >You told: "For program 'F' single-CPU system 'O' is 30% faster than system 'P', >so quad system 'O' is definitely faster than quad system 'P'". > >I answered: "Not necessary. For (another) program 'C' (prior to my NUMA >modifications) single-CPU system 'O' is faster than system 'I', bud quad system >'O' is noticeable slower than quad system 'I'". > >Yes, I did not have the exact numbers for Fritz. But the numbers I have suggest >that quad system 'P' can in fact be faster than system 'O'. It's hard to say >without measuring... > >Thanks, >Eugene I was just stating at this point it would be easier, and the best bet, to use a quad Opteron now rather than spend countless hours redoing the entire engine before an important match. You can get a good speed boost without optimizing. Just install it on the quad and let it rip. Even if they were going to recode the engine I'd bet the Opteron would require much less work than completely porting over to the Itanium. About your Itanium performance comment. I have yet to see anything of the sort. Mostly I hear of 'internal' benchmarks from Intel... then when the 'regular' people try those systems the benchmarks show a different story. I believe there was an article about this some time ago.. if I find it again I'll definitely post the link here. Also, crafty has some SMP problems with some systems. How are you certain that the particular problem in question did not come up? The Opteron has a memory channel per cpu resulting in an excellent speedups. On the dual Athlon system I saw speedups from 1.2x to 1.6x in crafty. Some people get 1.9x speedups in crafty.. my dual Celeron 400@552 gets 1.9 or so. It could have been a Crafty problem, not an Opteron problem. All of the other chess programs (such as fritz, deep junior, etc) had speedups of 1.85x or more on the dual Athlon however. I'd try some more reliable testing on the Itanium vs Opteron situation if I were you.
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