Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Gandalf HASH notice for all!!

Author: Ulrich Tuerke

Date: 04:33:58 01/09/01

Go up one level in this thread


On January 09, 2001 at 07:06:04, Jouni Uski wrote:

>On January 09, 2001 at 06:47:16, Ulrich Tuerke wrote:
>
>>On January 09, 2001 at 06:18:29, Steffen Jakob wrote:
>>
>>>On January 09, 2001 at 05:36:26, Ulrich Tuerke wrote:
>>>
>>>>On January 09, 2001 at 04:55:19, Jouni Uski wrote:
>>>>
>>>>>On January 09, 2001 at 04:08:38, Ulrich Tuerke wrote:
>>>>>
>>>>>>On January 09, 2001 at 03:09:39, Jouni Uski wrote:
>>>>>>
>>>>>>>If I am not complete wrong please note:
>>>>>>>
>>>>>>>Because Gandalf is so slow in NPS sense (about 1/4 of many top engines) it needs
>>>>>>>much less HASH table RAM than other programs and if You give too much HASH it
>>>>>>>weakens engine! So my recommendation:
>>>>>>>
>>>>>>>  500 Mhz PC 32MB
>>>>>>> 1000 Mhz PC 56MB
>>>>>>>
>>>>>>>The readme.txt to use 104MB for >128MB PC is not wise at all.
>>>>>>>
>>>>>>>Jouni
>>>>>>
>>>>>>I don't see, why "too much" hash could do any harm.
>>>>>>Uli
>>>>>
>>>>>I am not sure may be there is minor bug in hashing code. With 104MB (or similar)
>>>>>clearing of hash seems to take 5-10 seconds in my PC!
>>>>
>>>>This sounds weird. You shouldn't need 5-10 seconds for memory operations.
>>>>Perhaps your hash size is too close to your memory size and Windows starts
>>>>paging ?
>>>
>>>It depends if you simply clean the whole memory with zeroes or if you set a flag
>>>for each hash entry. In that case it is indeed better not to use large hash
>>>tables if you are low on time (e.g. in bullet games).
>>>
>>>Best wishes,
>>>Steffen.
>>
>>Come on, 5-10 seconds ! This must be massive hard disk access. A "memset" for
>>hundreds of MB can't take that long.
>
>It's not hard disk access - I have 192MB RAM installed and disk LED is not
>blinking either.
>
>Jouni

That's peculiar. Perhaps, Steen is doing something very special here with the
hash table ?
On my 450 Mhz PC, it takes certainly less than 1/2 second for Comet to intialize
a hash table of 78 MB.
Or has the hardware/operating system of some PCs to do additional efforts in
order to manage the memory above 64 MB ?

Uli



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.