pack: evict all of the pages at once

Somewhat surprisingly, this can increase the speed considerably, as we
don't bother trying to decide what to evict, and the most used entries
are quickly back into the cache.
This commit is contained in:
Carlos Martín Nieto 2013-01-14 17:42:12 +01:00
parent ed6648ba46
commit 9c62aaab40

View File

@ -116,49 +116,22 @@ static git_pack_cache_entry *cache_get(git_pack_cache *cache, git_off_t offset)
return entry; return entry;
} }
#define BASE_DELTA_EVICT_NR 8
/* Run with the cache lock held */ /* Run with the cache lock held */
static void free_lowest_entry(git_pack_cache *cache) static void free_lowest_entry(git_pack_cache *cache)
{ {
git_pack_cache_entry *entry; git_pack_cache_entry *entry;
khiter_t k; khiter_t k;
git_pack_cache_entry *lru[BASE_DELTA_EVICT_NR] = {NULL};
khiter_t lru_k[BASE_DELTA_EVICT_NR];
int i;
for (k = kh_begin(cache->entries); k != kh_end(cache->entries); k++) { for (k = kh_begin(cache->entries); k != kh_end(cache->entries); k++) {
if (!kh_exist(cache->entries, k)) if (!kh_exist(cache->entries, k))
continue; continue;
entry = kh_value(cache->entries, k); entry = kh_value(cache->entries, k);
for (i = 0; i < BASE_DELTA_EVICT_NR; i++) { if (entry && entry->refcount.val == 0) {
if (lru[i] == NULL || cache->memory_used -= entry->raw.len;
(entry->last_usage < lru[i]->last_usage && kh_del(off, cache->entries, k);
entry->refcount.val == 0)) { free_cache_object(entry);
int j;
for (j = 0; j < i; j++) {
lru[j] = lru[j+1];
lru_k[j] = lru_k[j+1];
}
lru[i] = entry;
lru_k[i] = k;
/* jump out and try with the next entry */
break;
}
}
}
for (i = 0; i < BASE_DELTA_EVICT_NR; i++) {
if (lru[i]) {
cache->memory_used -= lru[i]->raw.len;
kh_del(off, cache->entries, lru_k[i]);
free_cache_object(lru[i]);
} }
} }
} }