Author: Torstein Hall
Date: 10:11:24 08/24/04
Go up one level in this thread
On August 24, 2004 at 11:52:53, Robert Hyatt wrote: >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. Is it not a bit early to draw such a conlcusion after a 8 games match. I guess you have seen a lot longer series where the outscored program turns it around and scores better later on. And statistically I do not think it can be sayd 200 points with hig probability. Torstein > >> >>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...
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