Reporting top cpu and memory consumers via rappor on chromeos

chrome/browser/chromeos/resource_reporter/resource_reporter.h

Index: chrome/browser/chromeos/resource_reporter/resource_reporter.h
diff --git a/chrome/browser/chromeos/resource_reporter/resource_reporter.h b/chrome/browser/chromeos/resource_reporter/resource_reporter.h
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+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_
+#define CHROME_BROWSER_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/memory_pressure_listener.h"
+#include "base/memory/singleton.h"
+#include "base/time/time.h"
+#include "chrome/browser/task_management/task_manager_observer.h"
+#include "components/metrics/metrics_service.h"
+#include "components/rappor/sample.h"
+
+namespace chromeos {
+
+// A system that tracks the top |kTopConsumersCount| CPU and memory consumer
+// Chrome tasks and reports a weighted random sample of them via Rappor whenever
+// memory pressure is moderate or higher. The reporting is limited to once per
+// |kMinimumTimeBetweenReportsInMS|.
+class ResourceReporter : public task_management::TaskManagerObserver {
+ public:
+  // A collection of the data of a task manager's task that the ResourceReporter
+  // is interested in.
+  struct TaskRecord {
+    explicit TaskRecord(task_management::TaskId task_id);
+
+    TaskRecord(task_management::TaskId task_id,
+               const std::string& task_name,
+               double cpu_percent,
+               int64_t memory_bytest,

[Daniel Erat, 2015/11/24 22:03:52]

nit: "bytes"

[afakhry, 2015/11/24 22:49:49]

Done.

+               bool background);
+
+    // The ID of the task.
+    task_management::TaskId id;
+
+    // The canonicalized task name to be used to represent the task in a Rappor
+    // sample.
+    std::string task_name_for_rappor;
+
+    // The CPU usage of the task from the most recent task manager refresh in
+    // percentage [0.0, 100.0].
+    double cpu;

[Daniel Erat, 2015/11/24 22:03:52]

please rename this to "cpu_percent" too

[afakhry, 2015/11/24 22:49:49]

Done.

+
+    // The physical memory usage of the task from the most recent task manager
+    // refresh in bytes. It doesn't include shared memory. A value of -1 is
+    // invalid and means that the memory usage measurement for this task is not
+    // ready yet. See TaskManagerInterface::GetPhysicalMemoryUsage().
+    int64_t memory;

[Daniel Erat, 2015/11/24 22:03:52]

please rename this to "memory_bytes" too

[afakhry, 2015/11/24 22:49:49]

Done.

+
+    // True if the task is running on a process at background priority.
+    bool is_background;
+  };
+
+  ~ResourceReporter() override;
+
+  // The singleton instance.
+  static ResourceReporter* GetInstance();
+
+  // Start / stop observing the task manager and the memory pressure events.
+  void StartMonitoring();
+  void StopMonitoring();
+
+  // task_management::TaskManagerObserver:
+  void OnTaskAdded(task_management::TaskId id) override;
+  void OnTaskToBeRemoved(task_management::TaskId id) override;
+  void OnTasksRefreshed(const task_management::TaskIdList& task_ids) override;
+
+ private:
+  friend struct base::DefaultSingletonTraits<ResourceReporter>;
+  friend class ResourceReporterTest;
+  FRIEND_TEST_ALL_PREFIXES(ResourceReporterTest, TestGetCpuRapporMetricName);
+  FRIEND_TEST_ALL_PREFIXES(ResourceReporterTest, TestGetMemoryRapporMetricName);
+  FRIEND_TEST_ALL_PREFIXES(ResourceReporterTest, TestAll);
+
+  // WARNING: The below enum MUST never be renamed, modified or reordered, as
+  // they're written to logs. You can only insert a new element immediately
+  // before the last.
+  enum TaskProcessPriority {
+    FOREGROUND      = 0,

[Daniel Erat, 2015/11/24 22:03:52]

if these aren't enum classes, please rename them so it's more obvious which enum
they belong to, e.g.

PRIORITY_FOREGROUND
PRIORITY_BACKGROUND

CPU_USAGE_0_TO_10_PERCENT

MEMORY_USAGE_0_TO_200_MB

CPU_CORES_2_CORES

(i'd probably just rename the enum types to match too, e.g. Priority, CpuUsage,
MemoryUsage, CpuCores)

[afakhry, 2015/11/24 22:49:49]

Going the enum classes route with a *debatable* macro for doing the static casts
for less clutter.

+    BACKGROUND      = 1,
+    PRIORITIES_NUM  = 2,
+  };
+
+  // WARNING: The below enum MUST never be renamed, modified or reordered, as
+  // they're written to logs. You can only insert a new element immediately
+  // before the last.
+  enum CpuUsageRange {
+    RANGE_0_TO_10_PERCENT   = 0,
+    RANGE_10_TO_30_PERCENT  = 1,
+    RANGE_30_TO_60_PERCENT  = 2,
+    RANGE_ABOVE_60_PERCENT  = 3,
+    CPU_RANGES_NUM          = 4,
+  };
+
+  // WARNING: The below enum MUST never be renamed, modified or reordered, as
+  // they're written to logs. You can only insert a new element immediately
+  // before the last.
+  enum MemoryUsageRange {
+    RANGE_0_TO_200_MB    = 0,
+    RANGE_200_TO_400_MB  = 1,
+    RANGE_400_TO_600_MB  = 2,
+    RANGE_600_TO_800_MB  = 3,
+    RANGE_800_TO_1_GB    = 4,
+    RANGE_ABOVE_1_GB     = 5,
+    MEMORY_RANGES_NUM    = 6,
+  };
+
+  // WARNING: The below enum MUST never be renamed, modified or reordered, as
+  // they're written to logs. You can only insert a new element immediately
+  // before the last.
+  enum CpuCoresNumberRange {
+    RANGE_CORES_NA              = 0,
+    RANGE_CORES_1_CORE          = 1,
+    RANGE_CORES_2_CORES         = 2,
+    RANGE_CORES_3_TO_4_CORES    = 3,
+    RANGE_CORES_5_TO_8_CORES    = 4,
+    RANGE_CORES_9_TO_16_CORES   = 5,
+    RANGE_CORES_ABOVE_16_CORES  = 6,
+    CORES_RANGES_NUM            = 7,
+  };
+
+  // The maximum number of top consumer tasks of each resource that we're
+  // interested in reporting.
+  static const size_t kTopConsumersCount;
+
+  ResourceReporter();
+
+  // Creates a Rappor sample for the given |task_record|.
+  static scoped_ptr<rappor::Sample> CreateRapporSample(
+      rappor::RapporService* rappor_service,
+      const TaskRecord& task_record);
+
+  // Gets the CPU/memory usage ranges given the |cpu| / |memory_in_bytes|
+  // values.
+  static CpuUsageRange GetCpuUsageRange(double cpu);
+  static MemoryUsageRange GetMemoryUsageRange(int64_t memory_in_bytes);
+
+  // Gets the bucket in which the current system's number of CPU cores fall.
+  static CpuCoresNumberRange GetCurrentSystemCpuCoresRange();
+
+  // Perform a weighted random sampling to select a task by its CPU or memory
+  // usage weights so that we can record samples for them via Rappor.
+  // They return nullptr if no TaskRecord has been selected.
+  const TaskRecord* SampleTaskByCpu() const;
+  const TaskRecord* SampleTaskByMemory() const;
+
+  // The callback function that will be invoked on memory pressure events.
+  using MemoryPressureLevel = base::MemoryPressureListener::MemoryPressureLevel;
+  void OnMemoryPressure(MemoryPressureLevel memory_pressure_level);
+
+  // We'll use this to watch for memory pressure events so that we can trigger
+  // Rappor sampling at moderate memory pressure or higher.
+  scoped_ptr<base::MemoryPressureListener> memory_pressure_listener_;
+
+  // Contains the collected data about the currently running tasks from the most
+  // recent task manager refresh.
+  std::map<task_management::TaskId, scoped_ptr<TaskRecord>> task_records_;
+
+  // Contains the top |kTopConsumerCount| CPU consumer tasks sorted in a
+  // descending order by their CPU usage.
+  std::vector<TaskRecord*> task_records_by_cpu_;
+
+  // Contains the top |kTopConsumerCount| memory consumer tasks sorted in a
+  // descending order by their memory usage.
+  std::vector<TaskRecord*> task_records_by_memory_;
+
+  // The time at which the previous memory pressure event (moderate or higher)
+  // was received at which we recorded Rappor samples. This is used to limit
+  // generating a Rappor report to once per |kMinimumTimeBetweenReportsInMS|.
+  // This is needed to avoid generating a lot of samples that can lower the
+  // Rappor privacy guarantees.
+  base::TimeTicks last_memory_pressure_event_time_;
+
+  // The range that includes the number of CPU cores in the current system.
+  const CpuCoresNumberRange system_cpu_cores_range_;
+
+  // The most recent reading for the browser and GPU processes to be reported as
+  // UMA histograms when the system is under moderate memory pressure or higher.
+  double last_browser_process_cpu_ = 0.0;
+  double last_gpu_process_cpu_ = 0.0;
+  int64_t last_browser_process_memory_ = 0;
+  int64_t last_gpu_process_memory_ = 0;
+
+  // Tracks whether monitoring started or not.
+  bool is_monitoring_ = false;
+
+  // Whether we ever received a memory pressure event for the first time that is

[Daniel Erat, 2015/11/24 22:03:52]

"True after we've seen a high-pressure memory event." or something like that?

[afakhry, 2015/11/24 22:49:49]

Done.

+  // greater than or equal to a moderate pressure.
+  bool have_seen_first_memory_pressure_event_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceReporter);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_RESOURCE_REPORTER_RESOURCE_REPORTER_H_