Author: Aaron Gordon
Date: 20:55:53 11/12/03
Go up one level in this thread
On November 12, 2003 at 13:30:11, Robert Hyatt wrote: >On November 11, 2003 at 22:41:08, Aaron Gordon wrote: > >>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. >> > >The point being that this "problem" has been found and fixed. It was a >result of how AMD handles cache coherency vs Intel. And about what Intel >changed in the PIV cache coherency as well. The current version of >Crafty is back to scaling reasonably on my PIV xeon. Before it was not >doing well if you recall. We also had some ugly results from the Opteron >due to the NUMA problem. Much of that has been fixed and Crafty seems to >scale just fine there also. I'd hope that it now does pretty well on all >boxes, but it will take time to find out... Ah, thats good that it has been fixed. Any ideas when that particular version will be available for download? >>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.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.