components/metrics/call_stack_profile_builder.cc

   1 // Copyright 2018 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 "components/metrics/call_stack_profile_builder.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9 #include <utility>
  10
  11 #include "base/files/file_path.h"
  12 #include "base/lazy_instance.h"
  13 #include "base/logging.h"
  14 #include "base/metrics/metrics_hashes.h"
  15 #include "base/no_destructor.h"
  16 #include "base/stl_util.h"
  17 #include "components/metrics/call_stack_profile_encoding.h"
  18
  19 namespace metrics {
  20
  21 namespace {
  22
  23 // Only used by child processes.
  24 base::LazyInstance<ChildCallStackProfileCollector>::Leaky
  25     g_child_call_stack_profile_collector = LAZY_INSTANCE_INITIALIZER;
  26
  27 base::RepeatingCallback<void(base::TimeTicks, SampledProfile)>&
  28 GetBrowserProcessReceiverCallbackInstance() {
  29   static base::NoDestructor<
  30       base::RepeatingCallback<void(base::TimeTicks, SampledProfile)>>
  31       instance;
  32   return *instance;
  33 }
  34
  35 // Convert |filename| to its MD5 hash.
  36 uint64_t HashModuleFilename(const base::FilePath& filename) {
  37   const base::FilePath::StringType basename = filename.BaseName().value();
  38   // Copy the bytes in basename into a string buffer.
  39   size_t basename_length_in_bytes =
  40       basename.size() * sizeof(base::FilePath::CharType);
  41   std::string name_bytes(basename_length_in_bytes, '\0');
  42   memcpy(&name_bytes[0], &basename[0], basename_length_in_bytes);
  43   return base::HashMetricName(name_bytes);
  44 }
  45
  46 }  // namespace
  47
  48 CallStackProfileBuilder::CallStackProfileBuilder(
  49     const CallStackProfileParams& profile_params,
  50     base::OnceClosure completed_callback)
  51     : profile_start_time_(base::TimeTicks::Now()) {
  52   completed_callback_ = std::move(completed_callback);
  53   sampled_profile_.set_process(
  54       ToExecutionContextProcess(profile_params.process));
  55   sampled_profile_.set_thread(ToExecutionContextThread(profile_params.thread));
  56   sampled_profile_.set_trigger_event(
  57       ToSampledProfileTriggerEvent(profile_params.trigger));
  58 }
  59
  60 CallStackProfileBuilder::~CallStackProfileBuilder() = default;
  61
  62 // static
  63 void CallStackProfileBuilder::OnSampleCompleted(
  64     std::vector<base::StackSamplingProfiler::Frame> frames) {
  65   OnSampleCompleted(std::move(frames), 1);
  66 }
  67
  68 // TODO(chengx): record |count| as per-Stacksample metadata in the new proto
  69 // format.
  70 void CallStackProfileBuilder::OnSampleCompleted(
  71     std::vector<base::StackSamplingProfiler::Frame> frames,
  72     size_t /*count*/) {
  73   // Write CallStackProfile::Stack protobuf message.
  74   CallStackProfile::Stack stack;
  75
  76   for (const auto& frame : frames) {
  77     // keep the frame information even if its module is invalid so we have
  78     // visibility into how often this issue is happening on the server.
  79     CallStackProfile::Location* location = stack.add_frame();
  80     if (!frame.module.is_valid)
  81       continue;
  82
  83     // Dedup modules.
  84     const base::ModuleCache::Module& module = frame.module;
  85     auto module_loc = module_index_.find(module.base_address);
  86     if (module_loc == module_index_.end()) {
  87       modules_.push_back(module);
  88       size_t index = modules_.size() - 1;
  89       module_loc = module_index_.emplace(module.base_address, index).first;
  90     }
  91
  92     // Write CallStackProfile::Location protobuf message.
  93     ptrdiff_t module_offset =
  94         reinterpret_cast<const char*>(frame.instruction_pointer) -
  95         reinterpret_cast<const char*>(module.base_address);
  96     DCHECK_GE(module_offset, 0);
  97     location->set_address(static_cast<uint64_t>(module_offset));
  98     location->set_module_id_index(module_loc->second);
  99   }
 100
 101   CallStackProfile* call_stack_profile =
 102       sampled_profile_.mutable_call_stack_profile();
 103
 104   // Dedup Stacks.
 105   auto stack_loc = stack_index_.find(&stack);
 106   if (stack_loc == stack_index_.end()) {
 107     *call_stack_profile->add_stack() = std::move(stack);
 108     int stack_index = call_stack_profile->stack_size() - 1;
 109     // It is safe to store the Stack pointer because the repeated message
 110     // representation ensures pointer stability.
 111     stack_loc = stack_index_
 112                     .emplace(call_stack_profile->mutable_stack(stack_index),
 113                              stack_index)
 114                     .first;
 115   }
 116
 117   // Write CallStackProfile::StackSample protobuf message.
 118   CallStackProfile::StackSample* stack_sample_proto =
 119       call_stack_profile->add_stack_sample();
 120   stack_sample_proto->set_stack_index(stack_loc->second);
 121 }
 122
 123 void CallStackProfileBuilder::OnProfileCompleted(
 124     base::TimeDelta profile_duration,
 125     base::TimeDelta sampling_period) {
 126   // Build the SampledProfile protobuf message.
 127   CallStackProfile* call_stack_profile =
 128       sampled_profile_.mutable_call_stack_profile();
 129   call_stack_profile->set_profile_duration_ms(
 130       profile_duration.InMilliseconds());
 131   call_stack_profile->set_sampling_period_ms(sampling_period.InMilliseconds());
 132
 133   // Write CallStackProfile::ModuleIdentifier protobuf message.
 134   for (const auto& module : modules_) {
 135     CallStackProfile::ModuleIdentifier* module_id =
 136         call_stack_profile->add_module_id();
 137     module_id->set_build_id(module.id);
 138     module_id->set_name_md5_prefix(HashModuleFilename(module.filename));
 139   }
 140
 141   PassProfilesToMetricsProvider(std::move(sampled_profile_));
 142
 143   // Run the completed callback if there is one.
 144   if (!completed_callback_.is_null())
 145     std::move(completed_callback_).Run();
 146
 147   // Clear the caches.
 148   stack_index_.clear();
 149   module_index_.clear();
 150   modules_.clear();
 151 }
 152
 153 // static
 154 void CallStackProfileBuilder::SetBrowserProcessReceiverCallback(
 155     const base::RepeatingCallback<void(base::TimeTicks, SampledProfile)>&
 156         callback) {
 157   GetBrowserProcessReceiverCallbackInstance() = callback;
 158 }
 159
 160 // static
 161 void CallStackProfileBuilder::SetParentProfileCollectorForChildProcess(
 162     metrics::mojom::CallStackProfileCollectorPtr browser_interface) {
 163   g_child_call_stack_profile_collector.Get().SetParentProfileCollector(
 164       std::move(browser_interface));
 165 }
 166
 167 void CallStackProfileBuilder::PassProfilesToMetricsProvider(
 168     SampledProfile sampled_profile) {
 169   if (sampled_profile.process() == BROWSER_PROCESS) {
 170     GetBrowserProcessReceiverCallbackInstance().Run(profile_start_time_,
 171                                                     std::move(sampled_profile));
 172   } else {
 173     g_child_call_stack_profile_collector.Get()
 174         .ChildCallStackProfileCollector::Collect(profile_start_time_,
 175                                                  std::move(sampled_profile));
 176   }
 177 }
 178
 179 bool CallStackProfileBuilder::StackComparer::operator()(
 180     const CallStackProfile::Stack* stack1,
 181     const CallStackProfile::Stack* stack2) const {
 182   return std::lexicographical_compare(
 183       stack1->frame().begin(), stack1->frame().end(), stack2->frame().begin(),
 184       stack2->frame().end(),
 185       [](const CallStackProfile::Location& loc1,
 186          const CallStackProfile::Location& loc2) {
 187         return std::make_pair(loc1.address(), loc1.module_id_index()) <
 188                std::make_pair(loc2.address(), loc2.module_id_index());
 189       });
 190 }
 191
 192 }  // namespace metrics