c - How the Average Cache Miss Ratio (ACMR) is calculated? -

i'm studying tom forsyth's linear-speed vertex cache optimization , don't understand how calculates acmr. have read know acmr = number of cache misses / number of triangles, don't understand kind of cache being used (i.e. fifo or lru?).

i have written test program calculates , prints acmr of given 3d model using fifo cache, can please tell me if code ok? or should use lru cache instead?

/* number of entries in fifo cache */ #define fifo_cache_size     32  struct fifo_cache {     long entries[fifo_cache_size]; };  /**  * init_cache - initializes fifo cache  * @cache: pointer fifo cache structure initialized.  *  * before fifo cache can used, must initialized calling  * function.  */ static void init_cache(struct fifo_cache *cache) {     int = 0;      /* initialize cache entries invalid value */     (i = 0;i < fifo_cache_size;i++)         cache->entries[i] = -1; }  /**  * check_entry - checks if same entry added cache  * @cache: pointer fifo cache structure searched.  * @entry: entry searched for.  *  * return: if same entry found, return value nonzero. otherwise,  *         return value zero.  */ static int check_entry(const struct fifo_cache *cache, u16 entry) {     int = 0;      (i = 0;i < fifo_cache_size;i++) {         if (cache->entries[i] == (long)entry)             return 1;     }      return 0; }  /**  * add_entry - adds new entry fifo cache  * @cache: pointer fifo cache structure entry added to.  * @entry: entry add.  */ static void add_entry(struct fifo_cache *cache, u16 entry) {     long aux = 0;     long aux2 = 0;     int = 0;      aux = cache->entries[0];     cache->entries[0] = (long)entry;      (i = 1;i < fifo_cache_size;i++) {         aux2 = cache->entries[i];         cache->entries[i] = aux;         aux = aux2;     } }  /**  * calculate_acmr - calculates average cache miss ratio (aka. acmr)  * @indices: list of vertex indices.  * @count: number of vertex indices in @indices list.  */ float calculate_acmr(const u16 *indices, size_t count) {     struct fifo_cache cache = {0};     long total = 0; /* total number of cache misses */     long = 0;      /* initialize cache */     init_cache(&cache);      (i = 0;i < count;i++) {         if (!check_entry(&cache, indices[i])) {             /* entry doesn't exist in cache, add */             add_entry(&cache, indices[i]);              total++;         }     }      return ((float)total / (count / 3)); } 

you correct way hardware it. additionally may want read this: http://www.realtimerendering.com/blog/acmr-and-atvr/