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Robert Hyatt
Joined: 27 Feb 2006
Posts: 15819
Location: Birmingham, AL
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 Post subject: Re: question about symmertic evaluation Posted: Sat May 26, 2007 1:05 am |
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| Gerd Isenberg wrote: |
| bob wrote: |
However, when a program spends > 50% of the total search time inside the evaluation, 2-3 divides don't even show up in the timing and don't affect my NPS at all. Verified by lots of testing of course... |
I thought Crafty was in a ~1000 cycles range per node.
Thus 2-3 times 42 cycles don't looks negligible on a K8, where vector path idiv almost disables all parallel execution. So i guess you divide by constants, where the mentioned reciprocal or shift algorithms are applied by the compiler or code-generator.
http://swox.com/~tege/divcnst-pldi94.pdf |
I don't think so. I am searching about 1.7M nps on my core-2 duo at 2.0ghz. I guess I could use the hardware counters to count the number of instructions, but it has to be way more than 1000 instructions per node. Last time I did use hardware it was around 2700 instructions per node but that was probably 8-9 years ago and the new version has slowed down as we have added some eval stuff...
I looked at an old run where I divided by a variable (when I had variable scaling for endgame terms) and there was no difference in NPS....
I've seen others doing the same thing with the hash signature where it is modulo the hash table size to get the table index, and they apparently didn't feel it made enough difference compared with the AND and power-of-2 size limitation. |
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| Subject |
Author |
Date/Time |
 question about symmertic evaluation |
Uri Blass |
Wed May 23, 2007 7:53 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Wed May 23, 2007 8:45 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Wed May 23, 2007 8:46 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Wed May 23, 2007 9:04 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Wed May 23, 2007 9:51 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Wed May 23, 2007 10:04 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Wed May 23, 2007 10:09 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Thu May 24, 2007 12:01 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 7:37 am |
| Re: question about symmertic evaluation |
H.G.Muller |
Thu May 24, 2007 8:06 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 9:24 am |
| Re: question about symmertic evaluation |
H.G.Muller |
Thu May 24, 2007 10:39 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 11:36 am |
| Re: question about symmertic evaluation |
H.G.Muller |
Thu May 24, 2007 11:55 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 7:46 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Thu May 24, 2007 8:18 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 8:55 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Fri May 25, 2007 10:44 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Fri May 25, 2007 6:28 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Fri May 25, 2007 7:42 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Fri May 25, 2007 8:00 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Thu May 24, 2007 8:13 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Thu May 24, 2007 8:33 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Sat May 26, 2007 1:05 am |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Sat May 26, 2007 7:18 am |
| Re: question about symmertic evaluation |
Robert Hyatt |
Sat May 26, 2007 5:08 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Sat May 26, 2007 5:25 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Sat May 26, 2007 6:23 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Sun May 27, 2007 2:48 pm |
| Re: question about symmertic evaluation |
Steven Edwards |
Thu May 24, 2007 3:42 am |
| Re: question about symmertic evaluation |
Robert Hyatt |
Thu May 24, 2007 8:20 pm |
| Re: question about symmertic evaluation |
Robert Hyatt |
Wed May 23, 2007 9:50 pm |
| Re: question about symmertic evaluation |
William H. Rogers |
Fri May 25, 2007 7:48 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Sat May 26, 2007 11:38 am |
| Re: question about symmertic evaluation |
H.G.Muller |
Sat May 26, 2007 2:07 pm |
| Re: question about symmertic evaluation |
Vincent Diepeveen |
Sat May 26, 2007 7:27 pm |
| Re: question about symmertic evaluation |
Gerd Isenberg |
Sat May 26, 2007 8:20 pm |
| Re: question about symmertic evaluation |
Uri Blass |
Sat May 26, 2007 9:29 pm |
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