Author: Christophe Theron
Date: 09:30:20 04/27/01
Go up one level in this thread
On April 27, 2001 at 05:07:51, Robert Raese wrote:
>On April 27, 2001 at 03:13:31, Christophe Theron wrote:
>
>>On April 27, 2001 at 00:22:43, Robert Raese wrote:
>>
>>>On April 26, 2001 at 21:43:23, Christophe Theron wrote:
>>>
>>>>On April 26, 2001 at 20:38:18, Robert Raese wrote:
>>>>
>>>>>On April 26, 2001 at 20:36:25, Robert Raese wrote:
>>>>>
>>>>>>On April 26, 2001 at 20:15:47, Dan Andersson wrote:
>>>>>>
>>>>>>>That should be an easy one to answer, 192MB is maximum for Tiger and 16MB TBs
>>>>>>>are recommended. And thats way under 256 MB.
>>>>>>
>>>>>>i'd be interested to know how the figure 16MB was arrived at... if that is the
>>>>>>optimal setting for all time controls, or just for long games. i don't really
>>>>>>know the mechanism of how TBs are used by the program, so i'm wondering if
>>>>>>adding more RAM could help or even possibly hurt performance?
>>>>>
>>>>>* i meant adding more RAM to the TB cache.
>>>>
>>>>
>>>>
>>>>Well... My computer has only 96Mb RAM, so I cannot experiment up to 256Mb...
>>>>
>>>>But I think that adding TB cache will only increase performances, until you
>>>>reach a point where the OS has to swap data back to disk because your are using
>>>>more than the available RAM.
>>>
>>>how does the concept of "persistent hash" relate to this? also, if hash is
>>>persistent, does it persist between games, or just for the duration of the game?
>>>
>>>>
>>>> Christophe
>>
>>
>>
>>Persistent hash only relates to the main hash table, not the TB cache.
>>
>>In Tiger, the hash table is only cleared between games, never during a game.
>
>christophe,
>
>thanks for taking the time to answer beginner's questions. :)
>
>... and of course i have more... :)
>
>on my system, i see no difference between 48M or 192M for engine speed to d=11.
>at d=12 and d=13, 192M is faster. by the time tiger is reaching 13 deep in my
>test position, it is taking over 2 minutes to think. so i want to draw the
>conclusion that for blitz games 48M is plenty, BUT...
>
>since this test is only about one position for a couple of minutes, the main
>hash table doesn't fill up like it would during a game, does it? or is the
>engine faster at 192 because at 48 the hash is already filled in less than a
>minute, and previous data is already being overwritten?
Yes, it will be faster with 192Mb because things won't get overwritten as often
as with 48Mb.
But this is in absolute. In practice, you might never be able to see the
difference.
However if your computer has enough RAM, giving 192Mb, even at bullet time
controls, will NOT hurt.
In Tiger 12 there was a small penalty for huge hash tables, but since Tiger 13
this problem has disappeared. So the bigger the better.
>(i hope the chessassistant GUI will in the future give more engine data...
>there is an option "view hash" but it seems broken. when it is selected,
>nothing in the GUI or engine log changes... do you know if maybe this is some
>feature that was not implemented?)
The Tiger engines do not provide any function for reading the hash table
saturation level. So I guess the feature is available in the GUI for those
engines which will have the right function.
Christophe
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