[gnugo-devel] weird performance problem

[Arend Bayer]

Tracking back some spurious 50% slowdowns for regression runs,
I found out (with oprofile) that 50% of CPU time was spent in libc.
Not completely reproducable, however. In particular, I cannot
reproduce it when linked against libc_p (profiled version) instead of
libc.

According to top, gnugo is running with over 90% of CPU time, so
it should be caused by gnugo.
Does anybody have any idea what could cause this? Below is a flat
profile of libc during such a run (according to oprofile). An update
from SuSE 8.2 to 9.0 didn't solve the problem. 

Arend


Profiling through timer interrupt
samples  %        symbol name
6769     86.3393  __mcount_internal
665       8.4821  mcount
189       2.4107  __i686.get_pc_thunk.bx
170       2.1684  memset
27        0.3444  memcpy
6         0.0765  _int_malloc
3         0.0383  __GI___mbrtowc
2         0.0255  _int_free
1         0.0128  __GI___gettimeofday_internal
1         0.0128  __GI__dl_mcount_wrapper_check
1         0.0128  __malloc
1         0.0128  __realloc
1         0.0128  _int_realloc
1         0.0128  _nl_explode_name
1         0.0128  _nl_make_l10nflist
1         0.0128  index
1         0.0128  strlen