Disk Cache: Split some time histograms in groups based...

net/disk_cache/backend_impl.cc

 // Copyright (c) 2006-2008 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/backend_impl.h"
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/histogram.h"
 #include "base/message_loop.h"
@@ skipping 343 matching lines @@
     // The entry was already evicted.
     cache_entry->Release();
     stats_.OnEvent(Stats::OPEN_MISS);
     return false;
   }
 
   eviction_.OnOpenEntry(cache_entry);
   DCHECK(entry);
   *entry = cache_entry;
 
-  CACHE_UMA(AGE_MS, "OpenTime", 0, start);
+  CACHE_UMA(AGE_MS, "OpenTime", GetSizeGroup(), start);
   stats_.OnEvent(Stats::OPEN_HIT);
   return true;
 }
 
 bool BackendImpl::CreateEntry(const std::string& key, Entry** entry) {
   if (disabled_ || key.empty())
     return false;
 
   DCHECK(entry);
   *entry = NULL;
@@ skipping 57 matching lines @@
   block_files_.GetFile(entry_address)->Store(cache_entry->entry());
   block_files_.GetFile(node_address)->Store(cache_entry->rankings());
 
   IncreaseNumEntries();
   eviction_.OnCreateEntry(cache_entry);
   if (!parent.get())
     data_->table[hash & mask_] = entry_address.value();
 
   cache_entry.swap(reinterpret_cast<EntryImpl**>(entry));
 
-  CACHE_UMA(AGE_MS, "CreateTime", 0, start);
+  CACHE_UMA(AGE_MS, "CreateTime", GetSizeGroup(), start);
   stats_.OnEvent(Stats::CREATE_HIT);
   Trace("create entry hit ");
   return true;
 }
 
 bool BackendImpl::DoomEntry(const std::string& key) {
   if (disabled_)
     return false;
 
   Entry* entry;
@@ skipping 290 matching lines @@
 void BackendImpl::TooMuchStorageRequested(int32 size) {
   stats_.ModifyStorageStats(0, size);
 }
 
 std::string BackendImpl::HistogramName(const char* name, int experiment) {
   if (!experiment)
     return StringPrintf("DiskCache.%d.%s", cache_type_, name);
   return StringPrintf("DiskCache.%d.%s_%d", cache_type_, name, experiment);
 }
 
+int BackendImpl::GetSizeGroup() {
+  if (disabled_)
+    return 0;
+
+  // We want to report times grouped by the current cache size (50 MB groups).
+  int group = data_->header.num_bytes / (50 * 1024 * 1024);
+  if (group > 6)
+    group = 6;  // Limit the number of groups, just in case.
+  return group;
+}
+
 // We want to remove biases from some histograms so we only send data once per
 // week.
 bool BackendImpl::ShouldReportAgain() {
   if (uma_report_)
     return uma_report_ == 2;
 
   uma_report_++;
   int64 last_report = stats_.GetCounter(Stats::LAST_REPORT);
   Time last_time = Time::FromInternalValue(last_report);
   if (!last_report || (Time::Now() - last_time).InDays() >= 7) {
@@ skipping 755 matching lines @@
 
   return num_dirty;
 }
 
 bool BackendImpl::CheckEntry(EntryImpl* cache_entry) {
   RankingsNode* rankings = cache_entry->rankings()->Data();
   return !rankings->pointer;
 }
 
 }  // namespace disk_cache