Author: Robert Hyatt
Date: 08:29:43 08/25/05
Go up one level in this thread
On August 25, 2005 at 10:32:52, Vincent Diepeveen wrote: >On August 24, 2005 at 12:27:11, Robert Hyatt wrote: > >>On August 24, 2005 at 12:05:09, Vincent Diepeveen wrote: >> >>>On August 24, 2005 at 08:59:28, Thomas Logan wrote: >>> >>>>On August 24, 2005 at 08:47:33, Vincent Diepeveen wrote: >>>> >>>>>On August 24, 2005 at 08:20:25, Thomas Logan wrote: >>>>> >>>>>>Does anyone have scaling figures for various deep programs >>>>>> >>>>>>and systems with 2 dual core processors >>>>>> >>>>>>Tom >>>>> >>>>>hi, i just started a test at my k7 single cpu machine >>>>>to compare an output created at a quad dual core 1.8Ghz. >>>>> >>>>>The test is over 213 positiosn and statistical significant. >>>>> >>>>>I expect results within 2 weeks. >>>>> >>>>>You can calculate what time it takes 70 minutes * 213 positions. >>>>> >>>>>one thing already seems sure: >>>>> >>>>>x86-64 has no scaling problems with big hashtables, x86 has. >>>>> >>>>>Vincent >>>> >>>>Hello Vincent >>>> >>>>Thank you >>>> >>>>Are you using Diep ? >>>> >>>>Any knowledge concerning Fritz, Junior or Shredder >>>>Please post your results when obtained >>> >>>Shredder is scaling 3.3 at quad single core, so that'll be like scaling of 4 at >>>dual core quad or so? >>> >>>junior was single core and fritz will not be scaling well either (deepfritz8). >>> >>>We know all this already from 8 cpu Xeon machines in fact. See results donninger >>>posted once. >>> >>>If you don't run well at 8 cpu xeon then forget dual core. >> >> >>Not necessarily. 8cpu xeon was a kludge. Has same memory bandwidth as a 4-cpu >>xeon. Which means extra 4 cpus just cause a significant memory bottleneck. I >>ran on one of these multiple times. Programs with little memory traffic scale >>well, but those that require any reasonable memory access fall flat. Dual cores >>are not quite that bad but have the same basic problem, two cpus sharing a >>single hypertransport and single memory controller, so each node (AMD >>terminology) has internal contention that the single-core boxes do not. >> >>But the problems are solvable... except perhaps for the 8-way xeon which is >>just a bad box... at least the ones I tested on (Dell was one vendor) were... > >8 cpu Xeon was great for Diep. > >I tested at one of the sheikh's 8 cpu Xeons (no hyperthreading) and >it's very fast. > >Latency to memory is around 700ns when all 8 cpu's are busy. > >Perhaps not so great for Crafty, but diep can work excellent with it. > Fine. One I ran on was two 4-cpu systems tied together using the Intel Fusion chipset. Memory bandwidth was exactly the same for a 4 cpu box and an 8 cpu box, which means it was insufficient to keep 8 cpus running with Crafty. Other boxes run Crafty just fine, just not the 8-way xeon that I tested on... 8-way opterons, 16-way opterons and alphas, all work just great. And others... >> >>> >>>>Thanks again >>>> >>>>Tom
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