Allow for number of inflight pre*s to be experimented with

Bug: 1108891
Change-Id: I627b0ca7aa08dbe3717654ff6ba1cb9233237540
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2316324Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Sophie Chang <sophiechang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791913}

chrome/browser/predictors/preconnect_manager.cc

@@ -8,6 +8,7 @@
 
 #include "base/bind.h"
 #include "base/trace_event/trace_event.h"
+#include "chrome/browser/predictors/predictors_features.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -214,7 +215,7 @@ void PreconnectManager::TryToLaunchPreresolveJobs() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   while (!queued_jobs_.empty() &&
-         inflight_preresolves_count_ < kMaxInflightPreresolves) {
+         inflight_preresolves_count_ < features::GetMaxInflightPreresolves()) {
     auto job_id = queued_jobs_.front();
     queued_jobs_.pop_front();
     PreresolveJob* job = preresolve_jobs_.Lookup(job_id);

chrome/browser/predictors/preconnect_manager.h

@@ -145,8 +145,6 @@ class PreconnectManager {
         bool success) {}
   };
 
-  static const size_t kMaxInflightPreresolves = 3;
-
   PreconnectManager(base::WeakPtr<Delegate> delegate, Profile* profile);
   virtual ~PreconnectManager();
 

chrome/browser/predictors/preconnect_manager_unittest.cc

@@ -14,6 +14,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/predictors/loading_test_util.h"
+#include "chrome/browser/predictors/predictors_features.h"
 #include "chrome/browser/predictors/proxy_lookup_client_impl.h"
 #include "chrome/browser/predictors/resolve_host_client_impl.h"
 #include "chrome/test/base/testing_profile.h"
@@ -291,16 +292,16 @@ TEST_F(PreconnectManagerTest, TestStartOneUrlPreconnect_MultipleTimes) {
   GURL main_frame_url("http://google.com");
   net::NetworkIsolationKey network_isolation_key =
       CreateNetworkIsolationKey(main_frame_url);
-  size_t count = PreconnectManager::kMaxInflightPreresolves;
+  size_t count = features::GetMaxInflightPreresolves();
   std::vector<PreconnectRequest> requests;
   for (size_t i = 0; i < count + 1; ++i) {
-    // Exactly PreconnectManager::kMaxInflightPreresolves should be preresolved.
+    // Exactly features::GetMaxInflightPreresolves() should be preresolved.
     std::string url = base::StringPrintf("http://cdn%" PRIuS ".google.com", i);
     requests.emplace_back(url::Origin::Create(GURL(url)), 1,
                           network_isolation_key);
   }
   for (size_t i = 0; i < count; ++i) {
-    // Exactly PreconnectManager::kMaxInflightPreresolves should be initiated
+    // Exactly features::GetMaxInflightPreresolves() should be initiated
     // and preresolved.
     EXPECT_CALL(
         *mock_delegate_,
@@ -356,7 +357,7 @@ TEST_F(PreconnectManagerTest, TestTwoConcurrentMainFrameUrls_MultipleTimes) {
   GURL main_frame_url_1("http://google.com");
   net::NetworkIsolationKey network_isolation_key_1 =
       CreateNetworkIsolationKey(main_frame_url_1);
-  size_t count = PreconnectManager::kMaxInflightPreresolves;
+  size_t count = features::GetMaxInflightPreresolves();
   std::vector<PreconnectRequest> requests;
   for (size_t i = 0; i < count + 1; ++i) {
     std::string url = base::StringPrintf("http://cdn%" PRIuS ".google.com", i);
@@ -455,7 +456,7 @@ TEST_F(PreconnectManagerTest,
   GURL main_frame_url_1("http://google1.com");
   net::NetworkIsolationKey network_isolation_key_1 =
       CreateNetworkIsolationKey(main_frame_url_1);
-  size_t count = PreconnectManager::kMaxInflightPreresolves;
+  size_t count = features::GetMaxInflightPreresolves();
   std::vector<PreconnectRequest> requests;
   for (size_t i = 0; i < count - 1; ++i) {
     std::string url =
@@ -648,10 +649,10 @@ TEST_F(PreconnectManagerTest, TestUnqueuedPreresolvesCanceled) {
   GURL main_frame_url("http://google.com");
   net::NetworkIsolationKey network_isolation_key =
       CreateNetworkIsolationKey(main_frame_url);
-  size_t count = PreconnectManager::kMaxInflightPreresolves;
+  size_t count = features::GetMaxInflightPreresolves();
   std::vector<PreconnectRequest> requests;
   for (size_t i = 0; i < count; ++i) {
-    // Exactly PreconnectManager::kMaxInflightPreresolves should be preresolved.
+    // Exactly features::GetMaxInflightPreresolves() should be preresolved.
     std::string url = base::StringPrintf("http://cdn%" PRIuS ".google.com", i);
     requests.emplace_back(url::Origin::Create(GURL(url)), 1,
                           network_isolation_key);
@@ -843,7 +844,7 @@ TEST_F(PreconnectManagerTest, TestDetachedRequestHasHigherPriority) {
   GURL main_frame_url("http://google.com");
   net::NetworkIsolationKey network_isolation_key =
       CreateNetworkIsolationKey(main_frame_url);
-  size_t count = PreconnectManager::kMaxInflightPreresolves;
+  size_t count = features::GetMaxInflightPreresolves();
   std::vector<PreconnectRequest> requests;
   // Create enough asynchronous jobs to leave the last one in the queue.
   for (size_t i = 0; i < count; ++i) {

chrome/browser/predictors/predictors_features.cc

@@ -53,6 +53,10 @@ const base::FeatureParam<PrefetchSubresourceType>
         &kLoadingPredictorPrefetch, "subresource_type",
         PrefetchSubresourceType::kAll, &kPrefetchSubresourceTypeParamOptions};
 
+const base::Feature kLoadingPredictorInflightPredictiveActions{
+    "kLoadingPredictorInflightPredictiveActions",
+    base::FEATURE_ENABLED_BY_DEFAULT};
+
 bool ShouldUseLocalPredictions() {
   return base::FeatureList::IsEnabled(kLoadingPredictorUseLocalPredictions);
 }
@@ -65,4 +69,16 @@ bool ShouldUseOptimizationGuidePredictions() {
       kLoadingPredictorUseOptimizationGuide, "use_predictions", true);
 }
 
+size_t GetMaxInflightPreresolves() {
+  return static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
+      kLoadingPredictorInflightPredictiveActions, "max_inflight_preresolves",
+      3));
+}
+
+size_t GetMaxInflightPrefetches() {
+  return static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
+      kLoadingPredictorInflightPredictiveActions, "max_inflight_prefetches",
+      3));
+}
+
 }  // namespace features

chrome/browser/predictors/predictors_features.h

@@ -31,6 +31,8 @@ enum class PrefetchSubresourceType { kAll, kCss, kJsAndCss };
 extern const base::FeatureParam<PrefetchSubresourceType>
     kLoadingPredictorPrefetchSubresourceType;
 
+extern const base::Feature kLoadingPredictorInflightPredictiveActions;
+
 // Returns whether local predictions should be used to make preconnect
 // predictions.
 bool ShouldUseLocalPredictions();
@@ -43,6 +45,14 @@ bool ShouldUseLocalPredictions();
 // predictions should actually be used.
 bool ShouldUseOptimizationGuidePredictions();
 
+// Returns the maximum number of preresolves that can be inflight at any given
+// time.
+size_t GetMaxInflightPreresolves();
+
+// Returns the maximum number of prefetches that can be inflight at any given
+// time.
+size_t GetMaxInflightPrefetches();
+
 }  // namespace features
 
 #endif  // CHROME_BROWSER_PREDICTORS_PREDICTORS_FEATURES_H_

chrome/browser/predictors/prefetch_manager.cc

@@ -285,8 +285,10 @@ void PrefetchManager::OnPrefetchFinished(
 void PrefetchManager::TryToLaunchPrefetchJobs() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
-  if (queued_jobs_.empty() || inflight_jobs_count_ >= kMaxInflightJobs)
+  if (queued_jobs_.empty() ||
+      inflight_jobs_count_ >= features::GetMaxInflightPrefetches()) {
     return;
+  }
 
   // TODO(falken): Is it ok to assume the default partition? Try to plumb the
   // partition here, e.g., from WebContentsObserver. And make a similar change
@@ -296,7 +298,8 @@ void PrefetchManager::TryToLaunchPrefetchJobs() {
   scoped_refptr<network::SharedURLLoaderFactory> factory =
       storage_partition->GetURLLoaderFactoryForBrowserProcess();
 
-  while (!queued_jobs_.empty() && inflight_jobs_count_ < kMaxInflightJobs) {
+  while (!queued_jobs_.empty() &&
+         inflight_jobs_count_ < features::GetMaxInflightPrefetches()) {
     std::unique_ptr<PrefetchJob> job = std::move(queued_jobs_.front());
     queued_jobs_.pop_front();
     base::WeakPtr<PrefetchInfo> info = job->info;

chrome/browser/predictors/prefetch_manager.h

@@ -74,8 +74,6 @@ class PrefetchManager {
     virtual void PrefetchFinished(std::unique_ptr<PrefetchStats> stats) = 0;
   };
 
-  static const size_t kMaxInflightJobs = 3;
-
   PrefetchManager(base::WeakPtr<Delegate> delegate, Profile* profile);
   ~PrefetchManager();
 

chrome/browser/predictors/prefetch_manager_unittest.cc

@@ -182,7 +182,7 @@ TEST_F(PrefetchManagerTest, OneMainFrameUrlMultiplePrefetch) {
 
   // The ControllableHttpResponses must be made before the test server
   // is started.
-  for (size_t i = 0; i < PrefetchManager::kMaxInflightJobs + 1; i++) {
+  for (size_t i = 0; i < features::GetMaxInflightPrefetches() + 1; i++) {
     std::string path = base::StringPrintf("/script%" PRIuS ".js", i);
     paths.push_back(path);
     responses.push_back(
@@ -251,7 +251,7 @@ TEST_F(PrefetchManagerTest, MultipleMainFrameUrlMultiplePrefetch) {
   GURL main_frame_url2("https://def.invalid");
 
   // Set up prefetches one more than the inflight limit.
-  size_t count = PrefetchManager::kMaxInflightJobs;
+  size_t count = features::GetMaxInflightPrefetches();
 
   // The ControllableHttpResponses must be made before the test server
   // is started.
@@ -335,7 +335,7 @@ TEST_F(PrefetchManagerTest, Stop) {
   net::test_server::EmbeddedTestServer test_server;
 
   // Set up prefetches (limit + 1 for URL1, and 1 for URL2)
-  size_t limit = PrefetchManager::kMaxInflightJobs;
+  size_t limit = features::GetMaxInflightPrefetches();
 
   GURL main_frame_url("https://abc.invalid");
   std::vector<std::string> paths;
@@ -423,7 +423,7 @@ TEST_F(PrefetchManagerTest, StopAndStart) {
   net::test_server::EmbeddedTestServer test_server;
 
   // Set up prefetches (limit + 1).
-  size_t limit = PrefetchManager::kMaxInflightJobs;
+  size_t limit = features::GetMaxInflightPrefetches();
 
   GURL main_frame_url("https://abc.invalid");
   std::vector<std::string> paths;