Author: Robert Hyatt
Date: 13:02:51 06/05/03
Go up one level in this thread
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???
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