performance/stat-prefetch: Add accounting of cache hits and misses.

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 284 (performance actually decreases for 'ls -l' on a directory containing large number of files with stat-prefetch loaded)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=284

2 files changed, 17 insertions, 0 deletions

diff --git a/xlators/performance/stat-prefetch/src/stat-prefetch.c b/xlators/performance/stat-prefetch/src/stat-prefetch.c
index c5d05c4ae..4b44b3f45 100644
--- a/xlators/performance/stat-prefetch/src/stat-prefetch.c
+++ b/xlators/performance/stat-prefetch/src/stat-prefetch.c
@@ -558,6 +558,10 @@ sp_lookup (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xattr_req)
 
 wind:
         if (lookup_behind) {
+                if (cache) {
+                        cache->hits++;
+                }
+
                 wind_frame = copy_frame (frame);
                 if (wind_frame == NULL) {
                         op_ret = -1;
@@ -579,6 +583,10 @@ wind:
                 STACK_WIND (wind_frame, sp_lookup_behind_cbk, FIRST_CHILD(this),
                             FIRST_CHILD(this)->fops->lookup, loc, xattr_req);
         } else {
+                if (cache) {
+                        cache->miss++;
+                }
+
                 STACK_WIND (frame, sp_lookup_cbk, FIRST_CHILD(this),
                             FIRST_CHILD(this)->fops->lookup, loc, xattr_req);
      
@@ -1756,10 +1764,17 @@ sp_release (xlator_t *this, fd_t *fd)
         sp_fd_ctx_t *fd_ctx = NULL;
         uint64_t     value  = 0;
         int32_t      ret    = 0;
+        sp_cache_t  *cache  = NULL;
 
         ret = fd_ctx_del (fd, this, &value);
         if (!ret) {
                 fd_ctx = (void *)(long) value;
+                cache = fd_ctx->cache;
+                if (cache) {
+                        gf_log (this->name, GF_LOG_DEBUG, "cache hits: %lu, "
+                                "cache miss: %lu", cache->hits, cache->miss);
+                }
+
                 sp_fd_ctx_free (fd_ctx);      
         }
 
diff --git a/xlators/performance/stat-prefetch/src/stat-prefetch.h b/xlators/performance/stat-prefetch/src/stat-prefetch.h
index c17f96f24..2c5878ff5 100644
--- a/xlators/performance/stat-prefetch/src/stat-prefetch.h
+++ b/xlators/performance/stat-prefetch/src/stat-prefetch.h
@@ -37,6 +37,8 @@ struct sp_cache {
                                          * happen.
                                          */
         gf_lock_t   lock;
+        unsigned long miss;
+        unsigned long hits;
 };
 typedef struct sp_cache sp_cache_t;