Log predictor database size on startup

chrome/browser/net/predictor.cc

 // Copyright (c) 2012 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 "chrome/browser/net/predictor.h"
 
 #include <algorithm>
 #include <cmath>
 #include <set>
 #include <sstream>
@@ skipping 654 matching lines @@
   // on the same thread. The predictor lives on the IO thread and will die
   // from there so now that we're on the IO thread we need to properly
   // initialize the base::WeakPtrFactory.
   // TODO(groby): Check if WeakPtrFactory has the same constraint.
   weak_factory_.reset(new base::WeakPtrFactory<Predictor>(this));
 
   // Prefetch these hostnames on startup.
   DnsPrefetchMotivatedList(startup_urls, UrlInfo::STARTUP_LIST_MOTIVATED);
 
   DeserializeReferrersThenDelete(referral_list);
+
+  LogStartupMetrics();
 }
 
 //-----------------------------------------------------------------------------
 // This section intermingles prefetch results with actual browser HTTP
 // network activity.  It supports calculating of the benefit of a prefetch, as
 // well as recording what prefetched hostname resolutions might be potentially
 // helpful during the next chrome-startup.
 //-----------------------------------------------------------------------------
 
 void Predictor::LearnAboutInitialNavigation(const GURL& url) {
@@ skipping 480 matching lines @@
     return url;
   if (!transport_security_state_->ShouldUpgradeToSSL(url.host()))
     return url;
 
   url::Replacements<char> replacements;
   const char kNewScheme[] = "https";
   replacements.SetScheme(kNewScheme, url::Component(0, strlen(kNewScheme)));
   return url.ReplaceComponents(replacements);
 }
 
+void Predictor::LogStartupMetrics() {
+  size_t total_bytes = 0;
+  for (const auto& referrer : referrers_) {
+    total_bytes += referrer.first.spec().size();

[mmenke, 2016/06/20 17:01:24]

Could optionally add in in sizeof(ReferrerValue) here.

[Charlie Harrison, 2016/06/20 17:26:37]

Isn't that what sizeof(subresource.second) is doing below? Updated the code to
be a bit clear and added sizeof(Referrer) as well.

[mmenke, 2016/06/20 17:33:52]

Sorry, I meant sizeof(Referrer).  I find the object names here completely
unintuitive.  :(

[Charlie Harrison, 2016/06/20 17:35:13]

Agreed. Hoping to clean this up once we stop using Referer headers.

+    for (const auto& subresource: referrer.second) {

[mmenke, 2016/06/20 17:01:24]

nit:  Space before colon

[Charlie Harrison, 2016/06/20 17:26:37]

Done.

+      total_bytes += subresource.first.spec().size();
+      total_bytes += sizeof(subresource.second);
+    }
+  }
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Net.Predictor.Startup.DBSize", total_bytes, 1,
+                              1000000000, 50);

[mmenke, 2016/06/20 17:01:24]

Suggest reducing this to 10 MB to get a finer breakdown.  Also, please write
this as X * 1000 * 1000, to make it easier to read.

[Charlie Harrison, 2016/06/20 17:26:37]

Done.

+}
+
+
 // ---------------------- End IO methods. -------------------------------------
 
 //-----------------------------------------------------------------------------
 
 bool Predictor::PreconnectEnabled() const {
   base::AutoLock lock(preconnect_enabled_lock_);
   return preconnect_enabled_;
 }
 
 void Predictor::SetPreconnectEnabledForTest(bool preconnect_enabled) {
@@ skipping 131 matching lines @@
 }
 
 void SimplePredictor::ShutdownOnUIThread() {
   SetShutdown(true);
 }
 
 bool SimplePredictor::CanPrefetchAndPrerender() const { return true; }
 bool SimplePredictor::CanPreresolveAndPreconnect() const { return true; }
 
 }  // namespace chrome_browser_net