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Subject: Re: 64 bits report on diep

Author: Vincent Diepeveen

Date: 11:00:17 06/30/04

Go up one level in this thread


On June 30, 2004 at 13:22:31, Matthew Hull wrote:

>On June 30, 2004 at 13:15:02, Vincent Diepeveen wrote:
>
>>On June 30, 2004 at 13:13:19, Matthew Hull wrote:
>>
>>>On June 30, 2004 at 13:08:48, Gian-Carlo Pascutto wrote:
>>>
>>>>On June 30, 2004 at 13:06:24, Matthew Hull wrote:
>>>>
>>>>>On June 30, 2004 at 12:57:26, Vincent Diepeveen wrote:
>>>>>
>>>>>>Hello,
>>>>>>
>>>>>>For diep moving from 32 to 64 bits is not so interesting. But the 8==>16
>>>>>>registers is.
>>>>>>
>>>>>>All tested with same diep version :
>>>>>>
>>>>>>at windows 64 bits :
>>>>>>
>>>>>>net2003 32 bits : 135k nps
>>>>>>amd SDK 64 bits : 130k nps
>>>>>>gcc 3.4 32 bits : 130k nps  (with pgo)
>>>>>>
>>>>>>at linux (gentoo) 64 bits :
>>>>>>gcc 3.3.3 64 bits : 140k nps
>>>>>>
>>>>>>So it's trivial that moving from 8 to 16 registers increased it by 10k
>nps, >>>>>despite also losing to larger instruction sizes.
>>>>>
>>>>>
>>>>>
>>>>>If you had gone with bitboards, you would have seen a 47% increase.
>>>>
>>>>Which would have been no help if it had slowed him down 47% in 32 bit mode
>to >>>begin with.
>>>
>>>
>>>Do you think bitboards are that much slower on 32 bit machines?
>>
>>As proven 2 years ago clearly by me it is 2 times slower.
>>
>>Diep generates at 32 bits exactly 2 times faster than crafty.
>
>
>
>
>But "generates" is not a very big part of the program.  The program as a whole
>is 47% faster, not just move generation.

the invariants are used everywhere in evaluation to loop scan or whatever.
it's the basic principle simply that scanning in a simple 32 bits way goes
faster than getting first a bit out of bitboard and combining a lot of bitboards
with each other.

In 32 bits that's a lot slower.

Factor 2.2 initially, then some clever guys managed to speedup crafties bitboard
routines and it was factor 2.0 then.

>
>
>
>
>>Tested at K7. At P4 difference is bigger though.
>>
>>>
>>>>
>>>>--
>>>>GCP



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