src/chrome/browser/predictors/resource_prefetch_common.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/predictors/resource_prefetch_common.h"
   6
   7 #include <stdlib.h>
   8
   9 #include "base/command_line.h"
  10 #include "base/metrics/field_trial.h"
  11 #include "base/prefs/pref_service.h"
  12 #include "base/strings/string_split.h"
  13 #include "chrome/browser/net/prediction_options.h"
  14 #include "chrome/browser/profiles/profile.h"
  15 #include "chrome/common/chrome_switches.h"
  16 #include "content/public/browser/browser_thread.h"
  17 #include "content/public/browser/render_frame_host.h"
  18 #include "content/public/browser/render_process_host.h"
  19 #include "content/public/browser/web_contents.h"
  20
  21 using base::FieldTrialList;
  22 using std::string;
  23 using std::vector;
  24
  25 namespace predictors {
  26
  27 const char kSpeculativePrefetchingTrialName[] =
  28     "SpeculativeResourcePrefetching";
  29
  30 /*
  31  * SpeculativeResourcePrefetching is a field trial, and its value must have the
  32  * following format: key1=value1:key2=value2:key3=value3
  33  * e.g. "Prefetching=Enabled:Predictor=Url:Confidence=High"
  34  * The function below extracts the value corresponding to a key provided from
  35  * the SpeculativeResourcePrefetching field trial.
  36  */
  37 string GetFiledTrialSpecValue(string key) {
  38   vector<string> elements;
  39   base::SplitString(
  40       FieldTrialList::FindFullName(kSpeculativePrefetchingTrialName),
  41       ':',
  42       &elements);
  43   for (int i = 0; i < static_cast<int>(elements.size()); i++) {
  44     vector<string> key_value;
  45     base::SplitString(elements[i], '=', &key_value);
  46     if (key_value.size() == 2 && key_value[0] == key)
  47       return key_value[1];
  48   }
  49   return string();
  50 }
  51
  52 bool IsSpeculativeResourcePrefetchingEnabled(
  53     Profile* profile,
  54     ResourcePrefetchPredictorConfig* config) {
  55   DCHECK(config);
  56
  57   // Off the record - disabled.
  58   if (!profile || profile->IsOffTheRecord())
  59     return false;
  60
  61   // Enabled by command line switch. The config has the default params already
  62   // set. The command line with just enable them with the default params.
  63   if (CommandLine::ForCurrentProcess()->HasSwitch(
  64           switches::kSpeculativeResourcePrefetching)) {
  65     const std::string value =
  66         CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
  67             switches::kSpeculativeResourcePrefetching);
  68
  69     if (value == switches::kSpeculativeResourcePrefetchingDisabled) {
  70       return false;
  71     } else if (value == switches::kSpeculativeResourcePrefetchingLearning) {
  72       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
  73       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
  74       return true;
  75     } else if (value == switches::kSpeculativeResourcePrefetchingEnabled) {
  76       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
  77       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
  78       config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
  79       config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
  80       return true;
  81     }
  82   }
  83
  84   // Disable if no field trial is specified.
  85   std::string trial = base::FieldTrialList::FindFullName(
  86         kSpeculativePrefetchingTrialName);
  87   if (trial.empty())
  88     return false;
  89
  90   // Enabled by field trial.
  91   std::string spec_prefetching = GetFiledTrialSpecValue("Prefetching");
  92   std::string spec_predictor = GetFiledTrialSpecValue("Predictor");
  93   std::string spec_confidence = GetFiledTrialSpecValue("Confidence");
  94   std::string spec_more_resources = GetFiledTrialSpecValue("MoreResources");
  95   std::string spec_small_db = GetFiledTrialSpecValue("SmallDB");
  96
  97   if (spec_prefetching == "Learning") {
  98     if (spec_predictor == "Url") {
  99       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
 100     } else if (spec_predictor == "Host") {
 101       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
 102     } else {
 103       // Default: both Url and Host
 104       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
 105       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
 106     }
 107   } else if (spec_prefetching == "Enabled") {
 108     if (spec_predictor == "Url") {
 109       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
 110       config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
 111     } else if (spec_predictor == "Host") {
 112       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
 113       config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
 114     } else {
 115       // Default: both Url and Host
 116       config->mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
 117       config->mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
 118       config->mode |= ResourcePrefetchPredictorConfig::URL_PREFETCHING;
 119       config->mode |= ResourcePrefetchPredictorConfig::HOST_PRFETCHING;
 120     }
 121   } else {
 122     // Default: spec_prefetching == "Disabled"
 123     return false;
 124   }
 125
 126   if (spec_confidence == "Low") {
 127     config->min_url_visit_count = 1;
 128     config->min_resource_confidence_to_trigger_prefetch = 0.5f;
 129     config->min_resource_hits_to_trigger_prefetch = 1;
 130   } else if (spec_confidence == "High") {
 131     config->min_url_visit_count = 3;
 132     config->min_resource_confidence_to_trigger_prefetch = 0.9f;
 133     config->min_resource_hits_to_trigger_prefetch = 3;
 134   } else {
 135     // default
 136     config->min_url_visit_count = 2;
 137     config->min_resource_confidence_to_trigger_prefetch = 0.7f;
 138     config->min_resource_hits_to_trigger_prefetch = 2;
 139   }
 140
 141   if (spec_more_resources == "Enabled") {
 142     config->max_resources_per_entry = 100;
 143   }
 144
 145   if (spec_small_db == "Enabled") {
 146     config->max_urls_to_track = 200;
 147     config->max_hosts_to_track = 100;
 148   }
 149
 150   return true;
 151 }
 152
 153 NavigationID::NavigationID()
 154     : render_process_id(-1),
 155       render_frame_id(-1) {
 156 }
 157
 158 NavigationID::NavigationID(const NavigationID& other)
 159     : render_process_id(other.render_process_id),
 160       render_frame_id(other.render_frame_id),
 161       main_frame_url(other.main_frame_url),
 162       creation_time(other.creation_time) {
 163 }
 164
 165 NavigationID::NavigationID(content::WebContents* web_contents)
 166     : render_process_id(web_contents->GetRenderProcessHost()->GetID()),
 167       render_frame_id(web_contents->GetMainFrame()->GetRoutingID()),
 168       main_frame_url(web_contents->GetURL()) {
 169 }
 170
 171 bool NavigationID::is_valid() const {
 172   return render_process_id != -1 && render_frame_id != -1 &&
 173       !main_frame_url.is_empty();
 174 }
 175
 176 bool NavigationID::operator<(const NavigationID& rhs) const {
 177   DCHECK(is_valid() && rhs.is_valid());
 178   if (render_process_id != rhs.render_process_id)
 179     return render_process_id < rhs.render_process_id;
 180   else if (render_frame_id != rhs.render_frame_id)
 181     return render_frame_id < rhs.render_frame_id;
 182   else
 183     return main_frame_url < rhs.main_frame_url;
 184 }
 185
 186 bool NavigationID::operator==(const NavigationID& rhs) const {
 187   DCHECK(is_valid() && rhs.is_valid());
 188   return IsSameRenderer(rhs) && main_frame_url == rhs.main_frame_url;
 189 }
 190
 191 bool NavigationID::IsSameRenderer(const NavigationID& other) const {
 192   DCHECK(is_valid() && other.is_valid());
 193   return render_process_id == other.render_process_id &&
 194       render_frame_id == other.render_frame_id;
 195 }
 196
 197 ResourcePrefetchPredictorConfig::ResourcePrefetchPredictorConfig()
 198     : mode(0),
 199       max_navigation_lifetime_seconds(60),
 200       max_urls_to_track(500),
 201       max_hosts_to_track(200),
 202       min_url_visit_count(2),
 203       max_resources_per_entry(50),
 204       max_consecutive_misses(3),
 205       min_resource_confidence_to_trigger_prefetch(0.7f),
 206       min_resource_hits_to_trigger_prefetch(2),
 207       max_prefetches_inflight_per_navigation(24),
 208       max_prefetches_inflight_per_host_per_navigation(3) {
 209 }
 210
 211 ResourcePrefetchPredictorConfig::~ResourcePrefetchPredictorConfig() {
 212 }
 213
 214 bool ResourcePrefetchPredictorConfig::IsLearningEnabled() const {
 215   return IsURLLearningEnabled() || IsHostLearningEnabled();
 216 }
 217
 218 bool ResourcePrefetchPredictorConfig::IsPrefetchingEnabled(
 219     Profile* profile) const {
 220   return IsURLPrefetchingEnabled(profile) || IsHostPrefetchingEnabled(profile);
 221 }
 222
 223 bool ResourcePrefetchPredictorConfig::IsURLLearningEnabled() const {
 224   return (mode & URL_LEARNING) > 0;
 225 }
 226
 227 bool ResourcePrefetchPredictorConfig::IsHostLearningEnabled() const {
 228   return (mode & HOST_LEARNING) > 0;
 229 }
 230
 231 bool ResourcePrefetchPredictorConfig::IsURLPrefetchingEnabled(
 232     Profile* profile) const {
 233   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 234   if (!profile || !profile->GetPrefs() ||
 235       !chrome_browser_net::CanPrefetchAndPrerenderUI(profile->GetPrefs())) {
 236     return false;
 237   }
 238   return (mode & URL_PREFETCHING) > 0;
 239 }
 240
 241 bool ResourcePrefetchPredictorConfig::IsHostPrefetchingEnabled(
 242     Profile* profile) const {
 243   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 244   if (!profile || !profile->GetPrefs() ||
 245       !chrome_browser_net::CanPrefetchAndPrerenderUI(profile->GetPrefs())) {
 246     return false;
 247   }
 248   return (mode & HOST_PRFETCHING) > 0;
 249 }
 250
 251 bool ResourcePrefetchPredictorConfig::IsLowConfidenceForTest() const {
 252   return min_url_visit_count == 1 &&
 253       std::abs(min_resource_confidence_to_trigger_prefetch - 0.5f) < 1e-6 &&
 254       min_resource_hits_to_trigger_prefetch == 1;
 255 }
 256
 257 bool ResourcePrefetchPredictorConfig::IsHighConfidenceForTest() const {
 258   return min_url_visit_count == 3 &&
 259       std::abs(min_resource_confidence_to_trigger_prefetch - 0.9f) < 1e-6 &&
 260       min_resource_hits_to_trigger_prefetch == 3;
 261 }
 262
 263 bool ResourcePrefetchPredictorConfig::IsMoreResourcesEnabledForTest() const {
 264   return max_resources_per_entry == 100;
 265 }
 266
 267 bool ResourcePrefetchPredictorConfig::IsSmallDBEnabledForTest() const {
 268   return max_urls_to_track == 200 && max_hosts_to_track == 100;
 269 }
 270
 271 }  // namespace predictors