[freeciv-ai] (PR#6595) Optimize/reimplement CM

["Benoit Hudson" <bh@xxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=6595 >

> [i-freeciv-lists@xxxxxxxxxxxxx - Tue Nov 11 07:15:00 2003]:
> > It should be possible to speed it up using the caches: cache3 could be
> > an array indexed by city id; and we could start off with a check of
> > whether the city has changed in any way since we last optimized (are all
> > production values the same, and all the land is the same, same number of
> > citizens, same tiles open, ...).  If so, start from scratch.  This would
> > speed up buying buildings, for instance.
> 
> Yes it is possible. It will however increase the memory usage. Note
> that cache3 is 705kb.

cache3 is enormous because it allocates far more room for combinations
than it needs; dynamically allocating that room cut the space usage down
from over 50 Mb to under 7 on the server in a game with ~100 highly
developed cities.  Is that manageable?

I'm not confident the patch is as stable as alpha yet, but I'll play
around a bit.  Also, I want to check that it's actually faster.  The
cache3 hit rate is certainly up a lot just when loading the game, and I
expect it to be dramatically improved when you actually play.  It
remains to be seen if that translates to less time / call.