patchFreeciv - Patches: patch #3058, optimise time needed to creating a...

 
 
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patch #3058: optimise time needed to creating a savegame

Submitted by:  Matthias Pfafferodt <syntron>
Submitted on:  Wed 16 Nov 2011 09:28:24 PM UTC  
 
Category: generalPriority: 3 - Low
Status: NonePrivacy: Public
Assigned to: NoneOpen/Closed: Open
Planned Release: 

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Wed 16 Nov 2011 09:28:24 PM UTC, original submission:

from a message to the developer list (mail by Michal Mazurek):

> My sparc64 502mhz is taking 4 minutes now to /save a game. I
> tried poor mans optimization and inlined a couple of
> functions. I tested it on a 8x3400mhz intel i7. The test .serv
> was loading the game, and saving it 10 times. I managed to
> only go down to 11.76 from 13.56 seconds, that's not very
> much. Most of the time is spent doing real stuff, so i guess
> 500mhz is not adequate to run games with max map. About 5
> seconds of that time is just starting the server and loading
> the map.
>
> The function tile_index is called 495681563 times, I cant see
> how this can be cut down.
>
> sg_save_player_vision is called 370 times and takes most time,
> 12%. But it seems to be doing real stuff, also hard to cut
> down. And even if it is cut down, it's still only 12%.
>
> A decent computer saves the game rather fast, so I just guess
> my computer is just too old to run longturn games.


One thing to speed up saving a game would be a better handling of the saving each part of the map. In sg_save_player_vision() the macro SAVE_MAP_CHAR is called several times. Each (!) time it iterates over all tiles (= get tile from x, y coordinates) and saves only one part of the vision map definition (terrain, resources, (owner), specials, bases, update time). If this could be changed to one loop it would help.

Similar optimisation could be done for sg_save_map_known(); perhaps even all in one loop? (loop 1: y = lines; inner loop: x values; each part to be saved).

> However, I think that inlining functions like:
> int player_slot_count(void)
> {
> return (MAX_NUM_PLAYER_SLOTS);
> }
> would actually not only be faster, but also take less space.


I not sure that the rules are for inlining functions. In coding style only the use of inline functions instead of macros is stated.

Matthias Pfafferodt <syntron>
Project Member

 

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