Accumulate FileSystemUsageCache updates to improve write performance.

This change reduces the number of usage cache update on appending data to a file, and improves the write performance from 75.72 MB/s (σ = 23.255) to 229.238 MB/s (σ = 31.442) on a benchmark.

https://www.googledrive.com/host/0B0EZi1x_1MtFSnNRZy1nalVNdlk/append-write.html

BUG=166158

Review URL: https://codereview.chromium.org/11639037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175474 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 61 insertions, 6 deletions

diff --git a/webkit/fileapi/local_file_system_quota_unittest.cc b/webkit/fileapi/local_file_system_quota_unittest.cc
index 8ba84eb..f5f8bd8 100644
--- a/webkit/fileapi/local_file_system_quota_unittest.cc
+++ b/webkit/fileapi/local_file_system_quota_unittest.cc
@@ -88,6 +88,7 @@ class LocalFileSystemQuotaTest
   }
 
   int64 SizeByQuotaUtil() {
+    MessageLoop::current()->RunUntilIdle();
     return test_helper_.GetCachedOriginUsage();
   }
 
diff --git a/webkit/fileapi/obfuscated_file_util_unittest.cc b/webkit/fileapi/obfuscated_file_util_unittest.cc
index 349ee1c..c0d3e4e 100644
--- a/webkit/fileapi/obfuscated_file_util_unittest.cc
+++ b/webkit/fileapi/obfuscated_file_util_unittest.cc
@@ -229,6 +229,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
   }
 
   int64 SizeInUsageFile() {
+    MessageLoop::current()->RunUntilIdle();
     return FileSystemUsageCache::GetUsage(test_helper_.GetUsageCachePath());
   }
 
@@ -353,6 +354,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
           expected_usage_(expected_usage) {}
 
     ~UsageVerifyHelper() {
+      MessageLoop::current()->RunUntilIdle();
       Check();
     }
 
diff --git a/webkit/fileapi/sandbox_quota_observer.cc b/webkit/fileapi/sandbox_quota_observer.cc
index 29e1102..ec24d37 100644
--- a/webkit/fileapi/sandbox_quota_observer.cc
+++ b/webkit/fileapi/sandbox_quota_observer.cc
@@ -20,7 +20,9 @@ SandboxQuotaObserver::SandboxQuotaObserver(
     ObfuscatedFileUtil* sandbox_file_util)
     : quota_manager_proxy_(quota_manager_proxy),
       update_notify_runner_(update_notify_runner),
-      sandbox_file_util_(sandbox_file_util) {}
+      sandbox_file_util_(sandbox_file_util),
+      running_delayed_cache_update_(false),
+      weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {}
 
 SandboxQuotaObserver::~SandboxQuotaObserver() {}
 
@@ -37,11 +39,7 @@ void SandboxQuotaObserver::OnUpdate(const FileSystemURL& url,
                                     int64 delta) {
   DCHECK(SandboxMountPointProvider::CanHandleType(url.type()));
   DCHECK(update_notify_runner_->RunsTasksOnCurrentThread());
-  FilePath usage_file_path = GetUsageCachePath(url);
-  if (usage_file_path.empty())
-    return;
-  if (delta != 0)
-    FileSystemUsageCache::AtomicUpdateUsageByDelta(usage_file_path, delta);
+
   if (quota_manager_proxy_) {
     quota_manager_proxy_->NotifyStorageModified(
         quota::QuotaClient::kFileSystem,
@@ -49,14 +47,35 @@ void SandboxQuotaObserver::OnUpdate(const FileSystemURL& url,
         FileSystemTypeToQuotaStorageType(url.type()),
         delta);
   }
+
+  FilePath usage_file_path = GetUsageCachePath(url);
+  if (usage_file_path.empty())
+    return;
+
+  pending_update_notification_[usage_file_path] += delta;
+  if (!running_delayed_cache_update_) {
+    update_notify_runner_->PostTask(FROM_HERE, base::Bind(
+        &SandboxQuotaObserver::ApplyPendingUsageUpdate,
+        weak_factory_.GetWeakPtr()));
+    running_delayed_cache_update_ = true;
+  }
 }
 
 void SandboxQuotaObserver::OnEndUpdate(const FileSystemURL& url) {
   DCHECK(SandboxMountPointProvider::CanHandleType(url.type()));
   DCHECK(update_notify_runner_->RunsTasksOnCurrentThread());
+
   FilePath usage_file_path = GetUsageCachePath(url);
   if (usage_file_path.empty())
     return;
+
+  PendingUpdateNotificationMap::iterator found =
+      pending_update_notification_.find(usage_file_path);
+  if (found != pending_update_notification_.end()) {
+    UpdateUsageCacheFile(found->first, found->second);
+    pending_update_notification_.erase(found);
+  }
+
   FileSystemUsageCache::DecrementDirty(usage_file_path);
 }
 
@@ -83,4 +102,23 @@ FilePath SandboxQuotaObserver::GetUsageCachePath(const FileSystemURL& url) {
   return path;
 }
 
+void SandboxQuotaObserver::ApplyPendingUsageUpdate() {
+  for (PendingUpdateNotificationMap::iterator itr =
+           pending_update_notification_.begin();
+       itr != pending_update_notification_.end();
+       ++itr) {
+    UpdateUsageCacheFile(itr->first, itr->second);
+  }
+  pending_update_notification_.clear();
+  running_delayed_cache_update_ = false;
+}
+
+void SandboxQuotaObserver::UpdateUsageCacheFile(
+    const FilePath& usage_file_path,
+    int64 delta) {
+  DCHECK(!usage_file_path.empty());
+  if (!usage_file_path.empty() && delta != 0)
+    FileSystemUsageCache::AtomicUpdateUsageByDelta(usage_file_path, delta);
+}
+
 }  // namespace fileapi
diff --git a/webkit/fileapi/sandbox_quota_observer.h b/webkit/fileapi/sandbox_quota_observer.h
index d2d6326..4711ec0 100644
--- a/webkit/fileapi/sandbox_quota_observer.h
+++ b/webkit/fileapi/sandbox_quota_observer.h
@@ -5,12 +5,16 @@
 #ifndef WEBKIT_FILEAPI_SANDBOX_QUOTA_OBSERVER_H_
 #define WEBKIT_FILEAPI_SANDBOX_QUOTA_OBSERVER_H_
 
+#include <map>
+
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "webkit/fileapi/file_observers.h"
+#include "webkit/fileapi/file_system_url.h"
 
 namespace base {
 class SequencedTaskRunner;
@@ -29,6 +33,8 @@ class SandboxQuotaObserver
     : public FileUpdateObserver,
       public FileAccessObserver {
  public:
+  typedef std::map<FilePath, int64> PendingUpdateNotificationMap;
+
   SandboxQuotaObserver(
       quota::QuotaManagerProxy* quota_manager_proxy,
       base::SequencedTaskRunner* update_notify_runner,
@@ -44,6 +50,9 @@ class SandboxQuotaObserver
   virtual void OnAccess(const FileSystemURL& url) OVERRIDE;
 
  private:
+  void ApplyPendingUsageUpdate();
+  void UpdateUsageCacheFile(const FilePath& usage_file_path, int64 delta);
+
   FilePath GetUsageCachePath(const FileSystemURL& url);
 
   scoped_refptr<quota::QuotaManagerProxy> quota_manager_proxy_;
@@ -52,6 +61,11 @@ class SandboxQuotaObserver
   // Not owned; sandbox_file_util_ should have identical lifetime with this.
   ObfuscatedFileUtil* sandbox_file_util_;
 
+  PendingUpdateNotificationMap pending_update_notification_;
+  bool running_delayed_cache_update_;
+
+  base::WeakPtrFactory<SandboxQuotaObserver> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(SandboxQuotaObserver);
 };