Re: [Bug-gnubg] GNUbg crashes with Analyse - Distribution of Rolls

[Philippe Michel]

On Fri, 12 May 2017, motiv4u wrote:

> Start with a position (I think it can be just any position)
> GNUbg ID: bM7gASiYZ8oBMA:cAngAAAAAAAE
>
> Now do:
> Analyse - Distribution of rolls
> Change Depth from 1 to 2 to 3 to 4 to 5 (takes 10 minutes on i7 3th gen)
>
> With GNUbg build on Windows 10 (msys2) from CVS, May 7th, 2017
> continue playing: after couple of rolls, gnubg crashes
>
> With GNUbg from www.gnubg.org, version 1.05.00-mingw 32-Bit 20150725
> when depth 5 is almost done, a window pops up with:
> "GLib-ERROR (recursed) **:../../glib-2.44.1/glib/gmem.c:103: failed to
> allocate 12 bytes"
> and next lines identical with "failed to allocate 16, 704, 272 bytes"
> Click OK: GNUbg crashes.

Rolls distribution analysis can apparently use a lot of memory and leak 
it massively.

Looking a a ps output, I get something like this :

Initial :
USER        PID  %CPU %MEM     VSZ    RSS TT  STAT STARTED      TIME COMMAND
pm         1453   0.8  2.6  490968 211980  4  S+   18:38     0:00.96 ./gnubg

After depth 5 analysis :
pm         1453   0.0 13.3 1375704 1098672  4  I+   18:38     7:01.79 ./gnubg
About 800 MB used...

After OK and moving to another move :
pm         1453   1.7  7.4  888280 609976  4  S+   18:38     7:05.35 ./gnubg

After anoter depth 5 analysis :
pm         1453   0.0 16.1 1609176 1331752  4  S+   18:38     14:16.61 ./gnubg

After OK and moving to another move :
pm         1453   4.6 10.6 1156568 879024  4  S+   18:38     14:19.73 ./gnubg

etc...

I don't know much about gtk programming but the gtkrolls.c file is 
relatively short and the leak issue may be obvious to someone 
knowledgeable in this area.

On the other hand, I don't know why looking at rolls up to such a depth 
would be useful. To analyse market losing sequences, depth 2 seems enough 
(and then evaluate the leaf nodes at 0, 1, or 2 ply, but build a list of 
only 21^2 rolls sequences, not 21^5...).

For now, a simple way to avoid the problem would be to limit the usable 
depth to 4. Is there a reason you needed to go to 5 ?