Add process lifetime annotations to stack samples.

components/metrics/call_stack_profile_metrics_provider.cc

 // Copyright 2015 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 "components/metrics/call_stack_profile_metrics_provider.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 15 matching lines @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
 
 using base::StackSamplingProfiler;
 
 namespace metrics {
 
 namespace {
 
+// Provide a mapping from the C++ "enum" definition of various process phases
+// to the equivalent protobuf "enum" definition. This table-lookup conversion
+// allows for the implementation to evolve and still be compatible with the
+// protobuf -- even if there are ever more than 32 defined proto values, though
+// never more than 32 could be in-use in a given C++ version of the code.
+const ProcessPhase
+    kProtoPhases[CallStackProfileMetricsProvider::PHASES_MAX_VALUE] = {
+        ProcessPhase::MAIN_LOOP_START,
+        ProcessPhase::MAIN_NAVIGATION_START,
+        ProcessPhase::MAIN_NAVIGATION_FINISHED,
+        ProcessPhase::FIRST_NONEMPTY_PAINT,
+
+        ProcessPhase::SHUTDOWN_START,
+};
+
 // ProfilesState --------------------------------------------------------------
 
 // A set of profiles and the CallStackProfileMetricsProvider state associated
 // with them.
 struct ProfilesState {
   ProfilesState(const CallStackProfileParams& params,
                 base::StackSamplingProfiler::CallStackProfiles profiles,
                 base::TimeTicks start_timestamp);
   ProfilesState(ProfilesState&&);
   ProfilesState& operator=(ProfilesState&&);
@@ skipping 170 matching lines @@
   memcpy(&name_bytes[0], &basename[0], basename_length_in_bytes);
   return base::HashMetricName(name_bytes);
 }
 
 // Transcode |sample| into |proto_sample|, using base addresses in |modules| to
 // compute module instruction pointer offsets.
 void CopySampleToProto(
     const StackSamplingProfiler::Sample& sample,
     const std::vector<StackSamplingProfiler::Module>& modules,
     CallStackProfile::Sample* proto_sample) {
-  for (const StackSamplingProfiler::Frame& frame : sample) {
+  for (const StackSamplingProfiler::Frame& frame : sample.frames) {
     CallStackProfile::Entry* entry = proto_sample->add_entry();
     // A frame may not have a valid module. If so, we can't compute the
     // instruction pointer offset, and we don't want to send bare pointers, so
     // leave call_stack_entry empty.
     if (frame.module_index == StackSamplingProfiler::Frame::kUnknownModuleIndex)
       continue;
     int64_t module_offset =
         reinterpret_cast<const char*>(frame.instruction_pointer) -
         reinterpret_cast<const char*>(modules[frame.module_index].base_address);
     DCHECK_GE(module_offset, 0);
     entry->set_address(static_cast<uint64_t>(module_offset));
     entry->set_module_id_index(frame.module_index);
   }
 }
 
+// Transcode Sample annotations into protobuf fields. The C++ code uses a bit-
+// field with each bit corresponding to an entry in an enumeration while the
+// protobuf uses a repeated field of individual values. Conversion tables
+// allow for arbitrary mapping, though no more than 32 in any given version
+// of the code.
+void CopyAnnotationsToProto(uint32_t new_phases,
+                            CallStackProfile::Sample* sample_proto) {
+  for (size_t bit = 0; new_phases != 0 && bit < sizeof(new_phases) * 8; ++bit) {
+    const uint32_t flag = 1U << bit;
+    if (new_phases & flag) {
+      if (bit >= arraysize(kProtoPhases)) {
+        NOTREACHED();
+        continue;
+      }
+      sample_proto->add_process_phase(kProtoPhases[bit]);
+      new_phases ^= flag;  // Bit is set so XOR will clear it.
+    }
+  }
+}
+
 // Transcode |profile| into |proto_profile|.
 void CopyProfileToProto(
     const StackSamplingProfiler::CallStackProfile& profile,
     CallStackProfileParams::SampleOrderingSpec ordering_spec,
     CallStackProfile* proto_profile) {
   if (profile.samples.empty())
     return;
 
   if (ordering_spec == CallStackProfileParams::PRESERVE_ORDER) {
     // Collapse only consecutive repeated samples together.
     CallStackProfile::Sample* current_sample_proto = nullptr;
+    uint32_t phases = 0;
     for (auto it = profile.samples.begin(); it != profile.samples.end(); ++it) {
+      // Check if the sample is different than the previous one. Samples match
+      // if the frame and all annotations are the same.
       if (!current_sample_proto || *it != *(it - 1)) {
         current_sample_proto = proto_profile->add_sample();
         CopySampleToProto(*it, profile.modules, current_sample_proto);
         current_sample_proto->set_count(1);
+        CopyAnnotationsToProto(it->process_phases & ~phases,
+                               current_sample_proto);
+        phases = it->process_phases;
       } else {
         current_sample_proto->set_count(current_sample_proto->count() + 1);
       }
     }
   } else {
     // Collapse all repeated samples together.
     std::map<StackSamplingProfiler::Sample, int> sample_index;
+    uint32_t phases = 0;
     for (auto it = profile.samples.begin(); it != profile.samples.end(); ++it) {
+      // Check for a sample already seen. Samples match if the frame and all
+      // annotations are the same.
       auto location = sample_index.find(*it);
       if (location == sample_index.end()) {
         CallStackProfile::Sample* sample_proto = proto_profile->add_sample();
         CopySampleToProto(*it, profile.modules, sample_proto);
         sample_proto->set_count(1);
+        CopyAnnotationsToProto(it->process_phases & ~phases, sample_proto);
         sample_index.insert(
             std::make_pair(
                 *it, static_cast<int>(proto_profile->sample().size()) - 1));
+        phases = it->process_phases;
       } else {
         CallStackProfile::Sample* sample_proto =
             proto_profile->mutable_sample()->Mutable(location->second);
         sample_proto->set_count(sample_proto->count() + 1);
       }
     }
   }
 
   for (const StackSamplingProfiler::Module& module : profile.modules) {
     CallStackProfile::ModuleIdentifier* module_id =
@@ skipping 159 matching lines @@
 
 // static
 bool CallStackProfileMetricsProvider::IsReportingEnabledByFieldTrial() {
   const std::string group_name = base::FieldTrialList::FindFullName(
       CallStackProfileMetricsProvider::kFieldTrialName);
   return group_name ==
       CallStackProfileMetricsProvider::kReportProfilesGroupName;
 }
 
 }  // namespace metrics