diff options
author | Raghavendra G <raghavendra@gluster.com> | 2009-10-28 04:46:25 +0000 |
---|---|---|
committer | Anand V. Avati <avati@dev.gluster.com> | 2009-10-29 10:07:49 -0700 |
commit | 14962ce3e69e452a2447c12cde3369759365fda9 (patch) | |
tree | 19702c29142c35e05a1548f9471c77f6a4eab05e /xlators/performance/io-cache/src/io-cache.c | |
parent | 13e6947744e8a26d2380af200942fd4ed61fd845 (diff) |
performance/io-cache: change the hash function used for rbtree based hash table.
- the earlier hash function does not distribute pages uniformly for offsets that
fit into 32 bits. The reason is that the hash function just xors the contents of
the key 4 bytes at a time with the current value of hash. Hence for keys that
fit into 32 bits, the hash will be the key itself. Since we are using the
rounded_offset (which is a multiple of 128KB) as the key, the key will
be exactly divisible by the number of buckets configured (4096) resolving all
the pages into the first bucket.
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>
BUG: 335 (Io-cache optimization)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=335
Diffstat (limited to 'xlators/performance/io-cache/src/io-cache.c')
-rw-r--r-- | xlators/performance/io-cache/src/io-cache.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/xlators/performance/io-cache/src/io-cache.c b/xlators/performance/io-cache/src/io-cache.c index 5c1f74db1..da3f4f15d 100644 --- a/xlators/performance/io-cache/src/io-cache.c +++ b/xlators/performance/io-cache/src/io-cache.c @@ -30,6 +30,8 @@ #include <assert.h> #include <sys/time.h> +extern int ioc_log2_page_size; + uint32_t ioc_get_priority (ioc_table_t *table, const char *path); @@ -1234,11 +1236,12 @@ out: int32_t init (xlator_t *this) { - ioc_table_t *table = NULL; - dict_t *options = this->options; - uint32_t index = 0; - char *cache_size_string = NULL; - int32_t ret = -1; + ioc_table_t *table = NULL; + dict_t *options = this->options; + uint32_t index = 0; + char *cache_size_string = NULL; + int32_t ret = -1; + glusterfs_ctx_t *ctx = NULL; if (!this->children || this->children->next) { gf_log (this->name, GF_LOG_ERROR, @@ -1320,6 +1323,9 @@ init (xlator_t *this) this->private = table; ret = 0; + ctx = this->ctx; + ioc_log2_page_size = gf_log2 (ctx->page_size); + out: if (ret == -1) { if (table != NULL) { |