Histograms for DOMStorage access

content/renderer/renderer_webstoragearea_impl.cc

 // Copyright (c) 2011 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 "content/renderer/renderer_webstoragearea_impl.h"
 
+#include "base/metrics/histogram.h"
+#include "base/time.h"
 #include "content/common/dom_storage_messages.h"
 #include "content/renderer/render_thread_impl.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebStorageNamespace.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebURL.h"
 
 using WebKit::WebStorageNamespace;
 using WebKit::WebString;
 using WebKit::WebURL;
 
 RendererWebStorageAreaImpl::RendererWebStorageAreaImpl(
     int64 namespace_id, const WebString& origin) {
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_StorageAreaId(namespace_id, origin,
                                           &storage_area_id_));
 }
 
 RendererWebStorageAreaImpl::~RendererWebStorageAreaImpl() {
 }
 
 unsigned RendererWebStorageAreaImpl::length() {
   unsigned length;
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_Length(storage_area_id_, &length));
+  UMA_HISTOGRAM_TIMES("DOMStorage.length", base::Time::Now() - start);

[darin (slow to review), 2011/11/01 05:31:49]

it seems like we should have a convenience macro for cases like this:

  UMA_HISTOGRAM_TIMES_FOR_SCOPE

it could lay down a class, who's constructor would initialize the start time,
and who's destructor would do what UMA_HISTOGRAM_TIMES does.

[cbentzel, 2011/11/01 11:37:52]

Yes. I'll see how common this is. Most of the timing histograms I've added have
straddled across async callbacks, so the macro would not be useful then unless
it could get tied to a scoped_ptr.  

   return length;
 }
 
 WebString RendererWebStorageAreaImpl::key(unsigned index) {
   NullableString16 key;
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_Key(storage_area_id_, index, &key));
+  UMA_HISTOGRAM_TIMES("DOMStorage.key", base::Time::Now() - start);
   return key;
 }
 
 WebString RendererWebStorageAreaImpl::getItem(const WebString& key) {
   NullableString16 value;
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_GetItem(storage_area_id_, key, &value));
+  UMA_HISTOGRAM_TIMES("DOMStorage.getItem", base::Time::Now() - start);
   return value;
 }
 
 void RendererWebStorageAreaImpl::setItem(
     const WebString& key, const WebString& value, const WebURL& url,
     WebStorageArea::Result& result, WebString& old_value_webkit) {
   const size_t kMaxKeyValueLength = WebStorageNamespace::m_localStorageQuota;
   if (key.length() + value.length() > kMaxKeyValueLength) {
     result = ResultBlockedByQuota;
     return;
   }
   NullableString16 old_value;
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(new DOMStorageHostMsg_SetItem(
       storage_area_id_, key, value, url, &result, &old_value));
+  UMA_HISTOGRAM_TIMES("DOMStorage.setItem", base::Time::Now() - start);
   old_value_webkit = old_value;
 }
 
 void RendererWebStorageAreaImpl::removeItem(
     const WebString& key, const WebURL& url, WebString& old_value_webkit) {
   NullableString16 old_value;
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_RemoveItem(storage_area_id_, key, url, &old_value));
+  UMA_HISTOGRAM_TIMES("DOMStorage.removeItem", base::Time::Now() - start);
   old_value_webkit = old_value;
 }
 
 void RendererWebStorageAreaImpl::clear(
     const WebURL& url, bool& cleared_something) {
+  base::Time start = base::Time::Now();
   RenderThreadImpl::current()->Send(
       new DOMStorageHostMsg_Clear(storage_area_id_, url, &cleared_something));
+  UMA_HISTOGRAM_TIMES("DOMStorage.clear", base::Time::Now() - start);
 }