🚀 go-pugleaf

Dietmar Braun (dietmar@techfak.uni-bielefeld.de) wrote:
:   Hello everybody,

: I'm using Linux, the OS of a GNU generation :-) and I had to twiddle a
: little bit to get xboard and gnuchess compiled for linux. I asked in
: the linux news groups if somebody had interest in the binaries, which
: was a perfect way to fill up my mailbox. Since I've made the binaries
: available, I often get complaints about gnuchess swapping the system to
: death. 

: Gnuchess without any changes in the source takes 8MB when running. I want to
: compile and upload binaries which take about 2 and about 4 MB. I thought about 
: changing some definitions in gnuchess.h and would be very interested, 
: if someone could explain me the effect of changing ttblsz and undefining 
: huge in gnuchess.h. I would like to add some documentation how these changes
: affect play. I plan to let xboard do some matches of different 
: binaries against each other. 
: Anybody out there, who can help me?

There is one bit of important information that you neglected to mention
and that is the patch level of Gnuchess which you are working with.
Beginning with patchlevel 61, a static evaluation cache was added.  This
static cache is huge (with an entry being about 170 bytes long).

Of course the other array that takes up most of the memory is the
transposition table.  Each entry is pretty small (1 long + 2 char + 2
shorts).          

The transposition table is much more important then the static cache, so
it would be both advisable and beneficial to reduce the size of the
static cache.  The size is given as #define ETABLE xxxx in gnuchess.h
and you can tweak it to see if you can achieve 4M & 2M versions.  In
fact you might want to avoid tweaking this value and remove static
caching altogether.  This can be done by leaving out the -DCACHE macro
definition in the makefile.

Regards.

Chua KS