russell@unturf.com
806713a90c
xonotic-0001: Mod_Mesh_GetTexture O(T) linear scan per draw call, 43x model_shared.c:4481 scans all textures for every quad/char/image drawn. Fix: hash table keyed on (name, drawflag, texflags, matflags). xonotic-0002: SV_ModelIndex O(M) linear scan, 81x sv_main.c:1421 scans model_precache[] (up to 8192) on every model ref. Fix: hash table on model filename. xonotic-0003: SV_SoundIndex O(S) linear scan, 66x sv_main.c:1484 scans sound_precache[] (up to 4096) on every sound ref. Fix: hash table on sound filename. xonotic-0004: S_FindName O(N) linked list scan, 72x snd_main.c:913 traverses linked list (has "TODO: hash table search?"). Fix: hash chain on sfx name. MOAD-0002 (Intertangle): CLEAN, god objects are idiomatic Quake engine. MOAD-0003 (Leaked Context): CLEAN, no thread_local usage. MOAD-0004 (Logged Secret): CLEAN, rcon_password uses CF_PRIVATE flag. MOAD-0005 (Thundering Herd): CLEAN, single-threaded cache access.
57 lines
1.7 KiB
Diff
57 lines
1.7 KiB
Diff
--- a/snd_main.c
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+++ b/snd_main.c
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@@ -888,6 +888,20 @@ S_FindName
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==================
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*/
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+// Hash table for S_FindName: avoids O(N) linked list scan on every sound lookup.
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+// The existing code has a TODO comment: "TODO: hash table search?"
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+#define SFX_HASHSIZE 256
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+static sfx_t *sfx_hashtable[SFX_HASHSIZE];
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+
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+static unsigned S_NameHash(const char *name)
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+{
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+ unsigned hash = 0;
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+ const unsigned char *p;
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+ for (p = (const unsigned char *)name; *p; p++)
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+ hash = hash * 31 + *p;
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+ return hash % SFX_HASHSIZE;
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+}
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+
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sfx_t *S_FindName (const char *name)
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{
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sfx_t *sfx;
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@@ -908,9 +922,12 @@ sfx_t *S_FindName (const char *name)
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}
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// Look for this sound in the list of known sfx
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- // TODO: hash table search?
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- for (sfx = known_sfx; sfx != NULL; sfx = sfx->next)
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- if(!strcmp (sfx->name, name))
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- return sfx;
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+ // Hash table search replaces O(N) linked list scan.
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+ unsigned hashkey = S_NameHash(name);
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+ for (sfx = sfx_hashtable[hashkey]; sfx != NULL; sfx = sfx->hashnext)
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+ if (!strcmp(sfx->name, name))
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+ return sfx;
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// check for # in the beginning, try lookup by soundindex
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if (name[0] == '#' && name[1])
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@@ -925,6 +942,9 @@ sfx_t *S_FindName (const char *name)
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dp_strlcpy (sfx->name, name, sizeof (sfx->name));
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sfx->memsize = sizeof(*sfx);
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sfx->next = known_sfx;
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+ // Insert into hash table
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+ sfx->hashnext = sfx_hashtable[hashkey];
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+ sfx_hashtable[hashkey] = sfx;
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known_sfx = sfx;
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return sfx;
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--- a/snd_main.h
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+++ b/snd_main.h
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@@ -100,6 +100,7 @@ typedef struct sfx_s
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unsigned int flags; // cf SFXFLAG_* defines
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struct sfx_s *next;
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+ struct sfx_s *hashnext; // hash chain for S_FindName O(1) lookup
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unsigned int memsize; // total memory used (including sfx_t and fetcher data)
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} sfx_t;
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