Re: GnuBG doesn't use full cpu power

[Philippe Michel]

On Sun, Feb 23, 2020 at 03:29:09PM +0000, address@hidden wrote:

> I recently noticed that GnuBG doesn't use 100% of CPU when it's 
> searching for a hint or analyzing a game. It uses around 15% of CPU 
> power.
> I have increased Cache and Thread Count in settings but it didn't 
> change anything.
> Is it desired behavior or I need to change something to let it use all 
> CPU?

Hint doesn't use multithreading.

Analyzing a game of a match does but it doesn't do it perfectly 
efficiently as the number of threads grows. For instance, analyzing a 
match at 4ply with 16 threads (on a machine that has at least as many 
cores), I see the load average varying between 3-4 and 15-16, with an 
avarage of maybe 8-10. With only 2 or 4 cores, load averages would be 
someting like 2 and 3.5 respectively.

Rollouts use multithreading as well, and do it more efficiently. I'd 
exppect a rollout with 16 threads to be 12-15 times faster that with 
only one.

Cache size shouldn't make a difference. Don't set it to 0. Setting it 
higher than the default will help a little but this has nothing to do 
with multithreading. Don't set the threads count higher than the number 
of cores on your computer.

Could you tell more about your setup ? Whay OS and GNUbg version ? How 
many cores does your computer have and how many threads did you use ?