Disk cache: Finish the current experiment.

Review URL: http://codereview.chromium.org/67046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@13535 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 24 insertions, 52 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index 4984ecf..fd39495 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -135,13 +135,16 @@ bool DelayedCacheCleanup(const std::wstring& full_path) {
   return true;
 }
 
-// Sets |stored_value| for the current experiment.
-void InitExperiment(int* stored_value) {
-  if (*stored_value)
-    return;
+// Sets |stored_value| for the current experiment. Returns false if the files
+// should be discarded.
+bool InitExperiment(int* stored_value) {
+  if (*stored_value <= 2) {
+    *stored_value = 0;
+    return true;
+  }
 
-  // Don't add more people to the experiment; send them to group 1.
-  *stored_value = 1;
+  // Discard current cache for groups 3 and 4.
+  return false;
 }
 
 }  // namespace
@@ -214,8 +217,8 @@ bool BackendImpl::Init() {
   }
 
   init_ = true;
-  if (data_)
-    InitExperiment(&data_->header.experiment);
+  if (data_ && !InitExperiment(&data_->header.experiment))
+    return false;
 
   if (!CheckIndex()) {
     ReportError(ERR_INIT_FAILED);
@@ -898,20 +901,16 @@ void BackendImpl::AdjustMaxCacheSize(int table_len) {
 
   // Let's not use more than the default size while we tune-up the performance
   // of bigger caches. TODO(rvargas): remove this limit.
-  // If we are creating the file, use 1 as the multiplier so the table size is
-  // the same for everybody.
-  int multiplier = table_len ? data_->header.experiment : 1;
-  DCHECK(multiplier > 0 && multiplier < 5);
-  max_size_ = kDefaultCacheSize * multiplier;
+  if (max_size_ > kDefaultCacheSize)
+    max_size_ = kDefaultCacheSize;
 
   if (!table_len)
     return;
 
   // If we already have a table, adjust the size to it.
-  // NOTE: Disabled for the experiment.
-  // int current_max_size = MaxStorageSizeForTable(table_len);
-  // if (max_size_ > current_max_size)
-  //   max_size_= current_max_size;
+  int current_max_size = MaxStorageSizeForTable(table_len);
+  if (max_size_ > current_max_size)
+    max_size_= current_max_size;
 }
 
 void BackendImpl::RestartCache() {
@@ -936,9 +935,6 @@ void BackendImpl::PrepareForRestart() {
   rankings_.Reset();
   init_ = false;
   restarted_ = true;
-
-  // TODO(rvargas): remove this line at the end of this experiment.
-  max_size_ = 0;
 }
 
 int BackendImpl::NewEntry(Addr address, EntryImpl** entry, bool* dirty) {
@@ -1274,33 +1270,17 @@ void BackendImpl::LogStats() {
 }
 
 void BackendImpl::ReportStats() {
-  int experiment = data_->header.experiment;
-  CACHE_UMA(COUNTS, "Entries", experiment, data_->header.num_entries);
-  CACHE_UMA(COUNTS, "Size", experiment,
-             data_->header.num_bytes / (1024 * 1024));
-  CACHE_UMA(COUNTS, "MaxSize", experiment, max_size_ / (1024 * 1024));
+  CACHE_UMA(COUNTS, "Entries", 0, data_->header.num_entries);
+  CACHE_UMA(COUNTS, "Size", 0, data_->header.num_bytes / (1024 * 1024));
+  CACHE_UMA(COUNTS, "MaxSize", 0, max_size_ / (1024 * 1024));
 
   CACHE_UMA(COUNTS, "AverageOpenEntries", 0,
-             static_cast<int>(stats_.GetCounter(Stats::OPEN_ENTRIES)));
+            static_cast<int>(stats_.GetCounter(Stats::OPEN_ENTRIES)));
   CACHE_UMA(COUNTS, "MaxOpenEntries", 0,
-             static_cast<int>(stats_.GetCounter(Stats::MAX_ENTRIES)));
+            static_cast<int>(stats_.GetCounter(Stats::MAX_ENTRIES)));
   stats_.SetCounter(Stats::MAX_ENTRIES, 0);
 
-  if (!data_->header.create_time) {
-    // This is a client running the experiment on the dev channel.
-    CACHE_UMA(PERCENTAGE, "HitRatio", experiment, stats_.GetHitRatio());
-    stats_.ResetRatios();
-
-    if (!data_->header.num_bytes)
-      return;
-
-    int large_entries_bytes = stats_.GetLargeEntriesSize();
-    int large_ratio = large_entries_bytes * 100 / data_->header.num_bytes;
-    CACHE_UMA(PERCENTAGE, "LargeEntriesRatio", experiment, large_ratio);
-    return;
-  }
-
-  if (!data_->header.lru.filled)
+  if (!data_->header.create_time || !data_->header.lru.filled)
     return;
 
   // This is an up to date client that will report FirstEviction() data. After
@@ -1406,14 +1386,6 @@ bool BackendImpl::CheckIndex() {
   if (!mask_)
     mask_ = data_->header.table_len - 1;
 
-  // TODO(rvargas): remove this. For some reason, we are receiving crashes with
-  // mask_ being bigger than the actual table length. (bug 7217).
-  if (mask_ > 0xffff) {
-    LOG(ERROR) << "Invalid cache mask";
-    ReportError(ERR_INVALID_MASK);
-    return false;
-  }
-
   return true;
 }
 
diff --git a/net/disk_cache/backend_impl.h b/net/disk_cache/backend_impl.h
index 3fbc2a4..b1b6478 100644
--- a/net/disk_cache/backend_impl.h
+++ b/net/disk_cache/backend_impl.h
@@ -107,7 +107,7 @@ class BackendImpl : public Backend {
 
   // Returns the full histogram name, for the given base |name| and experiment,
   // and the current cache type. The name will be "DiskCache.t.name_e" where n
-  // is th ecache type and e the provided |experiment|.
+  // is the cache type and e the provided |experiment|.
   std::string HistogramName(const char* name, int experiment);
 
   net::CacheType cache_type() {
diff --git a/net/disk_cache/eviction.cc b/net/disk_cache/eviction.cc
index c000342..668fec2 100644
--- a/net/disk_cache/eviction.cc
+++ b/net/disk_cache/eviction.cc
@@ -142,7 +142,7 @@ void Eviction::ReportTrimTimes(EntryImpl* entry) {
   if (first_trim_) {
     first_trim_ = false;
     if (backend_->ShouldReportAgain()) {
-      CACHE_UMA(AGE, "TrimAge", header_->experiment, entry->GetLastUsed());
+      CACHE_UMA(AGE, "TrimAge", 0, entry->GetLastUsed());
     }
 
     if (header_->create_time && !header_->lru.filled) {