Author: Robert Hyatt
Date: 07:44:16 09/05/02
Go up one level in this thread
On September 05, 2002 at 10:36:36, Wayne Lowrance wrote: >On September 05, 2002 at 10:14:18, Robert Hyatt wrote: > >>On September 05, 2002 at 02:31:19, Slater Wold wrote: >> >>>On September 05, 2002 at 00:47:17, martin fierz wrote: >>> >>>>thanks, this is really interesting. i never realized that SMP searches could be >>>>so variable in some positions and very stable in others. >>>>actually, vincent might like this, because it's >2 speedup :-) >>>> >>>>aloha >>>> martin >>> >>>I have seen on my duals, more than once, an SMP program solve a problem in 3 >>>minutes. >>> >>>Then 2 hours later I try the same position and it solves it in 5 minutes. >>> >>>SMP is *way* to random in its branching to be what normal people call "stable". >> >> >>I take that variability as "part of the pain". But if you looked at the data >>I gave Martin, there _is_ something that is very troubling. In one of the >>runs, two processors were actually _slower_ than one. Granted that it is a >>pathological type of position, but anytime two is slower than one gets my >>attention in a big way. Bruce once sent me a position where four were >>1/10th as fast as one. I fooled with that for a long time before understanding >>it and improving the parallel search to fix it. > >Now this is the tone of discussion as it should be! My congratulations >Wayne "congratulations" are not necessary. Neither Slater nor myself started this mess. :) But thanks, anyway...
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