Author: Robert Hyatt
Date: 08:52:53 08/24/04
Go up one level in this thread
On August 24, 2004 at 11:00:18, Vincent Diepeveen wrote: >On August 24, 2004 at 10:42:51, Robert Hyatt wrote: > >>On August 24, 2004 at 09:06:05, Jorge Pichard wrote: >> >>>On August 24, 2004 at 06:16:26, Vincent Lejeune wrote: >>> >>>> >>>>A SYSTEM INTEGRATOR has started selling 5U eight way Opteron systems. >>>> >>>>http://www.theinquirer.net/?article=18035 >>>> >>>>I think it's the first 8-way system since the beginning of opteron. >>>> >>>>Great news for computer chess where a lot of 4 way was used in tournaments since >>>>1 year ! >>> >>> >>>It would had been a tough fight if shredder was using one against Hydra :-) >>> >>>Jorge >> >> >>1. It takes even more tuning as it is still a NUMA box. On the 4-way and 2-way >>boxes memory is local, 1 hop or 2 hops away. This adds to that. >> >>2. it won't be 2x faster as nobody scales perfectly. IE Crafty would probably > >Scaling = the increase in nodes a second. >Speedup (efficiency) = the speedup in time you get out of the box No. Those are _your_ definitions. traditional scaling means simply "as you increase the number of processors, how much does that reduce the total runtime." There are very _few_ applications that exhibit this NPS vs search time anomoly. Nobody cares in the world of parallel programming. I care because if I can't run 4x the NPS on 4 processors, I am losing something that I don't necessarily have to lose. Hence the stuff done before the WCCC to solve this on the opterons which started off producing pretty bad NPS increases. But the rest of the world only cares about total runtime... > >DIEP scales 100% on such 8 processor boxes. So do I. > >>be about 1.7X faster, more or less depending on lots of things. That is not >>enough to make up for the apparent difference in playing strength between >>Shredder and Hydra. IE Hydra appears to be 200+ points stronger based on a >>final result of 6-2. 1.7X faster won't get 200 points for Shredder... > >To my information Hydra runs currently on a 2 processor FPGA system. New fpga >processors, as chrilly is busy rewriting his parallel search. Web site contradicts that but since I don't have access to real data, I have no idea what they are running on. But based on the results against shredded, I really have trouble beliveing they are using just two processors. They apparently are at least 200 Elo stronger based on the match. > >He has to as they were talking already times ago about a 512 processor hydra >version (they = university paderborn which doesn't do the actual implementation >of the parallel algorithm, chrilly does do that). > >The current implementation of hydra doesn't store last 3 ply in software, not to >mention the last 3 ply in hardware, anything in hashtables. > >The entire hashtable from each node gets broadcasted to all other nodes and >stored there. > >That's a O(N^2) operation trivially and doesn't scale. > >The actual speedup of hydra is not objectively measured so far. Just claiming 12 >out of 16 without showing any actual data and already knowing that the single >cpu test doesn't use last 3 ply a hashtable, where any software program does do >that single cpu, is not a very nice comparision trivially. I haven't seen _any_ parallel search data other than my own, so all I can comment on is what I get... > >The 8 processor opteron cannot be compared with the cluster at which Hydra soon >again will run when the parallellism has been succesfully rewritten to something >that actually works better. > >The latency to do a single pingpong operation is 16 microseconds at the hardware >which is located in paderborn. Note that each node has 2 processors there and >the new hardware getting build in UAE is 2 machines of 8 processors connected to >each other. > >>These machines are not bad. There are _several_ companies with 8-way boxes > >There is not a single company selling 8 processor opteron boxes. It is well >known there are some beta versions of those boxes which several companies use to >test upon already for some years. Since I haven't tried to buy one, I won't comment. I _have_ run on one from two different vendors within the past 12 months. And Sun was advertising one a while back, whether they were shipping or not I can't say. > >>ready to go. I ran on one at least 6 months ago. AMD has had one in their >>development lab since well before the last CCT event...
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.