SimpleCache: more histograms watching how index is loaded.

net/disk_cache/simple/simple_index.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/disk_cache/simple/simple_index.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 389 matching lines @@
 
   const bool index_file_exists = file_util::PathExists(index_filename);
 
   // Only load if the index is not stale.
   const bool index_stale = SimpleIndex::IsIndexFileStale(index_filename);
   if (!index_stale) {
     const base::TimeTicks start = base::TimeTicks::Now();
     index_file_entries = SimpleIndexFile::LoadFromDisk(index_filename);
     UMA_HISTOGRAM_TIMES("SimpleCache.IndexLoadTime",
                         (base::TimeTicks::Now() - start));
+    UMA_HISTOGRAM_COUNTS("SimpleCache.IndexEntriesLoaded",
+                         index_file_entries->size());
   }
 
   UMA_HISTOGRAM_BOOLEAN("SimpleCache.IndexStale", index_stale);
 
   bool force_index_flush = false;
   if (!index_file_entries) {
     const base::TimeTicks start = base::TimeTicks::Now();
     index_file_entries = SimpleIndex::RestoreFromDisk(index_filename);
-    UMA_HISTOGRAM_TIMES("SimpleCache.IndexRestoreTime",
-                        (base::TimeTicks::Now() - start));
+    UMA_HISTOGRAM_MEDIUM_TIMES("SimpleCache.IndexRestoreTime",
+                               (base::TimeTicks::Now() - start));

[jar (doing other things), 2013/06/05 18:17:54]

nit: no need for redundant parens.  Good macro do this tsuff for you (if it
needs to be done ;-) ).

[pasko, 2013/06/05 18:39:37]

Done.

+    UMA_HISTOGRAM_COUNTS("SimpleCache.IndexEntriesRestored",
+                         index_file_entries->size());
 
     // When we restore from disk we write the merged index file to disk right
     // away, this might save us from having to restore again next time.
     force_index_flush = true;
   }
   UMA_HISTOGRAM_BOOLEAN("SimpleCache.IndexCorrupt",
                         (!index_stale && force_index_flush));
 
   // Used in histograms. Please only add new values at the end.
   enum {
@@ skipping 178 matching lines @@
                                                          entries_set_);
   cache_thread_->PostTask(FROM_HERE, base::Bind(
       &SimpleIndex::WriteToDiskInternal,
       index_filename_,
       base::Passed(&pickle),
       start,
       app_on_background_));
 }
 
 }  // namespace disk_cache