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Permit disabling of A* neighbor cache at compile-time

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Mostly to measure its effectiveness.  Compile with
AS_NO_NEIGHBOR_CACHE defined to disable it.

The neighbor cache turns out to be useless in my tests: it eats memory
without speeding up the update's distribution path assembly.
This commit is contained in:
Markus Armbruster 2011-02-20 08:43:44 +01:00
parent a02d3e9fc1
commit 7edcd3ea77
1 changed files with 8 additions and 0 deletions
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8
src/lib/common/path.c
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@ -40,6 +40,10 @@
* Define AS_NO_PATH_CACHE to disable the path cache. The path cache * Define AS_NO_PATH_CACHE to disable the path cache. The path cache
* saves a lot of work, but uses lots of memory. It should be a * saves a lot of work, but uses lots of memory. It should be a
* significant net win, unless you run out of memory. * significant net win, unless you run out of memory.
*
* Define AS_NO_NEIGHBOR_CACHE to disable the neighbor cache. The
* neighbor cache trades a modest amount of memory to save a bit of
* work. In its current form, it doesn't really make a difference.
*/ */
#include <config.h> #include <config.h>
@ -87,8 +91,10 @@ bp_init(void)
if (bp->adp == NULL) if (bp->adp == NULL)
return NULL; return NULL;
#ifndef AS_NO_NEIGHBOR_CACHE
if (neighsects == NULL) if (neighsects == NULL)
neighsects = calloc(WORLD_SZ() * 6, sizeof(struct sctstr *)); neighsects = calloc(WORLD_SZ() * 6, sizeof(struct sctstr *));
#endif
return bp; return bp;
} }
@ -125,8 +131,10 @@ best_path(struct sctstr *from, struct sctstr *to, char *path, int mob_type)
res = as_search(adp); res = as_search(adp);
#ifdef AS_STATS #ifdef AS_STATS
as_stats(adp, stderr); as_stats(adp, stderr);
#ifndef AS_NO_NEIGHBOR_CACHE
fprintf(stderr, "neighbor cache %zu bytes\n", fprintf(stderr, "neighbor cache %zu bytes\n",
WORLD_SZ() * 6 * sizeof(struct sctstr *)); WORLD_SZ() * 6 * sizeof(struct sctstr *));
#endif
#endif #endif
if (res < 0) if (res < 0)
return -1; return -1;