Author: Matthew White
Date: 16:21:46 06/05/03
Go up one level in this thread
On June 05, 2003 at 16:02:51, Robert Hyatt wrote: >On June 04, 2003 at 23:08:15, Matthew White wrote: > >>On June 04, 2003 at 22:24:59, Robert Hyatt wrote: >> >>>On June 04, 2003 at 18:32:43, Amir Ban wrote: >>> >>>>On June 04, 2003 at 14:54:30, Anson T J wrote: >>>> >>>>>Has anyone noticed if you do engine matches with Junior 8 / Deep Junior 8, ZX, >>>>>YY (any of them). If you set 1 thread per engine (on a dual machine), they share >>>>>1 cpu with a net cpu usage of 50% !! >>>>> >>>>>Deep Fritz 7, Shredder 7 / 7.04 and all other SMP engines I know of don't have >>>>>this problem. >>>>> >>>>>I guess the Junior 8 engines fix the affinity of the single cpu setup meaning in >>>>>an engine match or tournament they share the same cpu instead of using one each. >>>>> >>>> >>>>Didn't think of this, damn. >>>> >>>> >>>>>Any fixes known? >>>>> >>>> >>>>The problem should come up whenever running one DJ version against another with >>>>no. of threads set to less than no. of processors. I can't think of any >>>>workaround. I should get rid of processor affinity in that case. >>>> >>>>Amir >>> >>> >>>What's the reason for doing this? The O/S should handle this by itself and >>>avoid flipping a single process back and forth between physical processors, >>>without the program itself being involved in the decision... >> >>On a Dual-proc HT enabled system, you would want to make sure that your programs >>were getting 1 "real" CPU each and one "virtual one". I'm not sure that the OS >>would necessarily behave like that in every case. >> >>Matt > >Actually you would want two _real_ cpus, not one real and one virtual. > >But, in any case, this can't be the issue because how do you _know_ which >processor is real and which is virtual, when all you know is 0-n??? Lower numbers are real, I believe. The point that I was trying to make before is that rather than giving one engine two real cpus and one engine two virtual ones, you would want to partition the real and virtual ones equally. Bear in mind I was merely speculating as to Amir's motives, I don't know for sure. I can see the reasoning behind your point as well. Regards, Matt
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