[Freeciv-Dev] Re: Profiling Civserver again

[Vasco Alexandre Da Silva Costa <vasc@xxxxxxxxxxxxxx>]

Looking at the code some more functions can be inlined. I also noticed
somethings: for e.g.

=== map_adjust_x(X) on map.h:
The '(X) % map.xsize < 0' conditional can be replaced with '(X) < 0' which
is faster and is correct due to the following propositions being true (or
so i think):

the integer remainder operation '%' only provides negative results when
either the dividend or the divisor is negative.
map.xsize is always >= 0.

1264 int normalize_map_pos(int *x, int *y) {
1265   if (*y < 0 || *y >= map.ysize)
1266     return FALSE;
1267 
1268   while (*x < 0)
1269     *x += map.xsize;
1270   while (*x > map.xsize-1)
1271     *x -= map.xsize;
1272 
1273   return TRUE;
1274 }

Is grossly inneficient. This code should be equivalent:
int normalize_map_pos(int *x, int *y) {
  if (*y < 0 || *y >= map.ysize)
    return FALSE;
  *x = map_adjust_x(*x);
  return TRUE;
}

Still, looking at the results of the run that Paul provided, given that
this accounts for more than 4% of running time this function should be
inlined somehow. It really should be turned into some kind of macro since
all these pointers and the function call overheard for such a simple
function cause the slowdown.

This should work:
#define normalize_map_pos(X, Y) \
  ((X)=map_adjust_x(X), ((Y) >= 0 && (Y) < map.ysize))

But i guess it could be more efficient.

---
Vasco Alexandre da Silva Costa @ Instituto Superior Tecnico, Lisboa