Add UMA that periodically logs number of outstanding requests

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 39108877eb551027f55ebfd7e6d29a13dc89690d..71b316f31a1577be7f78ae2ae946034ac85103fc 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -78,6 +78,7 @@
 #include "content/common/resource_request.h"
 #include "content/common/resource_request_body_impl.h"
 #include "content/common/resource_request_completion_status.h"
+#include "content/common/site_isolation_policy.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/global_request_id.h"
@@ -168,6 +169,9 @@ static ResourceDispatcherHostImpl* g_resource_dispatcher_host;
 // The interval for calls to ResourceDispatcherHostImpl::UpdateLoadStates
 const int kUpdateLoadStatesIntervalMsec = 250;
 
+// The interval for calls to RecordOutstandingRequestsStats.
+const int kRecordOutstandingRequestsStatsIntervalMsec = 60000;
+
 // Maximum byte "cost" of all the outstanding requests for a renderer.
 // See declaration of |max_outstanding_requests_cost_per_process_| for details.
 // This bound is 25MB, which allows for around 6000 outstanding requests.
@@ -339,6 +343,8 @@ ResourceDispatcherHostImpl::ResourceDispatcherHostImpl(
           kMaxOutstandingRequestsCostPerProcess),
       largest_outstanding_request_count_seen_(0),
       largest_outstanding_request_per_process_count_seen_(0),
+      peak_outstanding_request_count_(0),

[Charlie Harrison, 2017/06/22 12:33:46]

These aren't necessary if they are declared in the h file.

[Kunihiko Sakamoto, 2017/06/23 04:22:06]

Done.

+      peak_outstanding_request_count_multitab_(0),
       delegate_(nullptr),
       loader_delegate_(nullptr),
       allow_cross_origin_auth_prompt_(false),
@@ -361,6 +367,7 @@ ResourceDispatcherHostImpl::ResourceDispatcherHostImpl(
       base::Bind(&ResourceDispatcherHostImpl::OnInit, base::Unretained(this)));
 
   update_load_states_timer_.reset(new base::RepeatingTimer());
+  record_outstanding_requests_stats_timer_.reset(new base::RepeatingTimer());

[Charlie Harrison, 2017/06/22 12:33:46]

nit: prefer base::MakeUnique to avoid bare new.

[Kunihiko Sakamoto, 2017/06/23 04:22:06]

Done.

 }
 
 // The default ctor is only used by unittests. It is reasonable to assume that
@@ -371,6 +378,7 @@ ResourceDispatcherHostImpl::ResourceDispatcherHostImpl()
 
 ResourceDispatcherHostImpl::~ResourceDispatcherHostImpl() {
   DCHECK(outstanding_requests_stats_map_.empty());
+  DCHECK(outstanding_requests_per_tab_map_.empty());
   DCHECK(g_resource_dispatcher_host);
   DCHECK(main_thread_task_runner_->BelongsToCurrentThread());
   g_resource_dispatcher_host = NULL;
@@ -589,13 +597,20 @@ bool ResourceDispatcherHostImpl::HandleExternalProtocol(ResourceLoader* loader,
 }
 
 void ResourceDispatcherHostImpl::DidStartRequest(ResourceLoader* loader) {
-  // Make sure we have the load state monitor running.
+  // Make sure we have the load state monitors running.
   if (!update_load_states_timer_->IsRunning() &&
       scheduler_->HasLoadingClients()) {
     update_load_states_timer_->Start(
         FROM_HERE, TimeDelta::FromMilliseconds(kUpdateLoadStatesIntervalMsec),
         this, &ResourceDispatcherHostImpl::UpdateLoadInfo);
   }
+  if (!record_outstanding_requests_stats_timer_->IsRunning()) {
+    record_outstanding_requests_stats_timer_->Start(
+        FROM_HERE,
+        TimeDelta::FromMilliseconds(
+            kRecordOutstandingRequestsStatsIntervalMsec),
+        this, &ResourceDispatcherHostImpl::RecordOutstandingRequestsStats);
+  }
 }
 
 void ResourceDispatcherHostImpl::DidReceiveRedirect(
@@ -784,10 +799,11 @@ void ResourceDispatcherHostImpl::OnShutdown() {
   is_shutdown_ = true;
   pending_loaders_.clear();
 
-  // Make sure we shutdown the timer now, otherwise by the time our destructor
+  // Make sure we shutdown the timers now, otherwise by the time our destructor
   // runs if the timer is still running the Task is deleted twice (once by
   // the MessageLoop and the second time by RepeatingTimer).
   update_load_states_timer_.reset();
+  record_outstanding_requests_stats_timer_.reset();
 
   // Clear blocked requests if any left.
   // Note that we have to do this in 2 passes as we cannot call
@@ -1919,6 +1935,26 @@ void ResourceDispatcherHostImpl::UpdateOutstandingRequestsStats(
     outstanding_requests_stats_map_[info.GetChildID()] = stats;
 }
 
+void ResourceDispatcherHostImpl::IncrementOutstandingRequestsPerTab(
+    int count,
+    const ResourceRequestInfoImpl& info) {
+  // No-op in OOPIF modes, because the routing id doesn't represent tabs.

[Charlie Harrison, 2017/06/22 12:33:46]

Can we just not initialize the timer in these cases? Checking command line flags
more often than necessary is a personal pet peeve :)

[Kunihiko Sakamoto, 2017/06/23 04:22:06]

Done.

+  if (SiteIsolationPolicy::UseDedicatedProcessesForAllSites() ||
+      SiteIsolationPolicy::IsTopDocumentIsolationEnabled() ||
+      SiteIsolationPolicy::AreIsolatedOriginsEnabled()) {
+    return;
+  }
+
+  auto key = std::make_pair(info.GetChildID(), info.GetRouteID());
+  OutstandingRequestsPerTabMap::iterator entry =
+      outstanding_requests_per_tab_map_.insert(std::make_pair(key, 0)).first;
+  entry->second += count;
+  DCHECK_GE(entry->second, 0);
+  if (entry->second == 0) {
+    outstanding_requests_per_tab_map_.erase(entry);
+  }
+}
+
 ResourceDispatcherHostImpl::OustandingRequestsStats
 ResourceDispatcherHostImpl::IncrementOutstandingRequestsMemory(
     int count,
@@ -1954,6 +1990,8 @@ ResourceDispatcherHostImpl::IncrementOutstandingRequestsCount(
   DCHECK_GE(stats.num_requests, 0);
   UpdateOutstandingRequestsStats(*info, stats);
 
+  IncrementOutstandingRequestsPerTab(count, *info);
+
   if (num_in_flight_requests_ > largest_outstanding_request_count_seen_) {
     largest_outstanding_request_count_seen_ = num_in_flight_requests_;
     UMA_HISTOGRAM_COUNTS_1M(
@@ -1969,6 +2007,15 @@ ResourceDispatcherHostImpl::IncrementOutstandingRequestsCount(
         largest_outstanding_request_per_process_count_seen_);
   }
 
+  if (num_in_flight_requests_ > peak_outstanding_request_count_) {
+    peak_outstanding_request_count_ = num_in_flight_requests_;
+  }
+
+  if (HasRequestsFromMultipleActiveTabs() &&
+      num_in_flight_requests_ > peak_outstanding_request_count_multitab_) {
+    peak_outstanding_request_count_multitab_ = num_in_flight_requests_;
+  }
+
   return stats;
 }
 
@@ -2497,6 +2544,23 @@ void ResourceDispatcherHostImpl::UpdateLoadInfo() {
       base::Bind(UpdateLoadStateOnUI, loader_delegate_, base::Passed(&infos)));
 }
 
+void ResourceDispatcherHostImpl::RecordOutstandingRequestsStats() {
+  if (peak_outstanding_request_count_ != 0) {
+    UMA_HISTOGRAM_COUNTS_1M(
+        "Net.ResourceDispatcherHost.PeakOutstandingRequests",
+        peak_outstanding_request_count_);
+    peak_outstanding_request_count_ = num_in_flight_requests_;
+  }
+
+  if (peak_outstanding_request_count_multitab_ != 0) {
+    UMA_HISTOGRAM_COUNTS_1M(
+        "Net.ResourceDispatcherHost.PeakOutstandingRequests.MultiTabLoading",
+        peak_outstanding_request_count_multitab_);
+    peak_outstanding_request_count_multitab_ =
+        HasRequestsFromMultipleActiveTabs() ? num_in_flight_requests_ : 0;
+  }
+}
+
 void ResourceDispatcherHostImpl::BlockRequestsForRoute(
     const GlobalFrameRoutingId& global_routing_id) {
   DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
@@ -2706,4 +2770,21 @@ ResourceDispatcherHostImpl::HandleDownloadStarted(
   return handler;
 }
 
+bool ResourceDispatcherHostImpl::HasRequestsFromMultipleActiveTabs() {
+  if (outstanding_requests_per_tab_map_.size() < 2)
+    return false;
+
+  int active_tabs = 0;
+  for (auto iter = outstanding_requests_per_tab_map_.begin();
+       iter != outstanding_requests_per_tab_map_.end(); ++iter) {
+    if (iter->second > 2) {
+      active_tabs++;
+      if (active_tabs >= 2) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 }  // namespace content