Author: Fabien Letouzey
Date: 05:50:51 03/26/04
Go up one level in this thread
On March 26, 2004 at 08:44:58, Slater Wold wrote: >On March 26, 2004 at 08:34:42, Fabien Letouzey wrote: > >>On March 26, 2004 at 08:14:41, Slater Wold wrote: >> >>>On March 26, 2004 at 04:26:03, Fabien Letouzey wrote: >>> >>>>On March 26, 2004 at 01:30:02, Slater Wold wrote: >>>> >>>>>32-bit: 907,446 N/sec (20s from starting position) >>>>> >>>>>64-bit: 816,815 N/sec (20s from starting position) >>>>> >>>>>/O2, /Ot, /Og, /Ob2 >>>>> >>>>> >>>>>If you're wondering, Fruit is not a bitboard program. :) >>>> >>>>Is this slow-down thing an isolated case? >>>> >>>>Fabien. >>> >>>Do you mean, is Fruit the only engine that slows down when compiled for 64-bit? >>> >>>Yes. >> >>I find it interesting; do you feel like investigating? > >Yes. I can, and will. I started looking last nite, but ran out of time. It's not urgent of course, but I think we've got something to learn. For instance a way not to do things for 64-bit platforms :) >>One drawback of 64-bit ints and pointers is that they could take more space in >>memory, but I thought I carefully avoided that everywhere ... >I am not sure what's slowing it down. I could clearly see why it might not get >a huge speedup, but the 10% slow down is confusing. I pass many pointers as function arguments (for instance I pass a pointer to the board everyhere instead of using a global variable). To me an argument is the same as a local variable, and the slow down is very small on 32-bit platforms I am sure. Also, I keep move lists and the PV in local stack frames, making stack usage quite large (although only a small part of the frame is used at each level). Do you think it could be the stack? Fabien.
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