Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Question to Bob: Crafty , Alpha and FindBit()

Author: Roland Pfister

Date: 03:20:27 06/08/98

Go up one level in this thread



On June 08, 1998 at 06:03:08, Ernst A. Heinz wrote:

>On June 05, 1998 at 21:48:57, Robert Hyatt wrote:
>
>>On June 05, 1998 at 17:47:07, Bruce Moreland wrote:
>>
>>>
>>>On June 05, 1998 at 08:53:53, Ernst A. Heinz wrote:
>>>
>>>>BTW, we have been waiting to get our hands on a Alpha-21264 for roughly
>>>>a year because "DarkThought" will hopefully speed up as much on them
>>>>as "Crafty".
>>>
>>>What percentage of execution time do you and Bob spend doing these
>>>operations, do you think?
>>>
>>>bruce
>>
>>FindFirstOne() = 1-2% in crafty.  popcnt is much less...  so that won't
>>help a whole lot.  but the 64 bit stuff helps in general...
>
>The greatest speedup I expect is not related to the "bean-counting" :-)
>execution time spent on the operations. Instead, our code will gain a
>lot
>in terms of simplicity w.r.t. to possible optimizations. Example: There
>are many loops over bitboards which need a function call to find the
>next
>bit prior to each iteration. Right now, these function calls never get
>inlined but with find-bit instructions they will thus opening the road
>for further optimizations ...

Why don't you inline those functions by hand now?

In the critical parts I inline my "get next bit" function, I also tried
it as a function call and hoped for better cache effects but in vain.

I  did the experiments on PC only not on Sparc or Alpha....

>
>=Ernst=



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.