Disk cache histograms tracking cache opens by size/age of cache.

These histograms compliment the other hit rate histograms I added in http://codereview.chromium.org/10911040/ , but instead of reporting by time interval, they report at each open. By comparing the Miss/Hit version of each histogram, you can get a rate in the same way that the stochastic interval-reporting version has.

This set of histograms will have different biasses than the time series data, as users who do a lot of operations will be represented more heavily.

As an added bonus, I'm also tracking the open time of cache misses, since that's shown up in http_cache_transaction as being interesting.

R=rvargas@chromium.org
BUG=None


Review URL: https://chromiumcodereview.appspot.com/10909126

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@156758 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 17 insertions, 6 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index 05094a0..2de5952 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -686,14 +686,22 @@ EntryImpl* BackendImpl::OpenEntryImpl(const std::string& key) {
 
   bool error;
   EntryImpl* cache_entry = MatchEntry(key, hash, false, Addr(), &error);
-  if (!cache_entry) {
-    stats_.OnEvent(Stats::OPEN_MISS);
-    return NULL;
-  }
-
-  if (ENTRY_NORMAL != cache_entry->entry()->Data()->state) {
+  if (cache_entry && ENTRY_NORMAL != cache_entry->entry()->Data()->state) {
     // The entry was already evicted.
     cache_entry->Release();
+    cache_entry = NULL;
+  }
+
+  int current_size = data_->header.num_bytes / (1024 * 1024);
+  int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120;
+  int64 no_use_hours = stats_.GetCounter(Stats::LAST_REPORT_TIMER) / 120;
+  int64 use_hours = total_hours - no_use_hours;
+
+  if (!cache_entry) {
+    CACHE_UMA(AGE_MS, "OpenTime.Miss", 0, start);
+    CACHE_UMA(COUNTS_10000, "AllOpenBySize.Miss", 0, current_size);
+    CACHE_UMA(HOURS, "AllOpenByTotalHours.Miss", 0, total_hours);
+    CACHE_UMA(HOURS, "AllOpenByUseHours.Miss", 0, use_hours);
     stats_.OnEvent(Stats::OPEN_MISS);
     return NULL;
   }
@@ -704,6 +712,9 @@ EntryImpl* BackendImpl::OpenEntryImpl(const std::string& key) {
   Trace("Open hash 0x%x end: 0x%x", hash,
         cache_entry->entry()->address().value());
   CACHE_UMA(AGE_MS, "OpenTime", 0, start);
+  CACHE_UMA(COUNTS_10000, "AllOpenBySize.Hit", 0, current_size);
+  CACHE_UMA(HOURS, "AllOpenByTotalHours.Hit", 0, total_hours);
+  CACHE_UMA(HOURS, "AllOpenByUseHours.Hit", 0, use_hours);
   stats_.OnEvent(Stats::OPEN_HIT);
   SIMPLE_STATS_COUNTER("disk_cache.hit");
   return cache_entry;