Task manager should support Idle Wakeups on Windows

chrome/browser/task_management/sampling/shared_sampler.h

+// Copyright 2016 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_TASK_MANAGEMENT_SAMPLING_SHARED_SAMPLER_H_
+#define CHROME_BROWSER_TASK_MANAGEMENT_SAMPLING_SHARED_SAMPLER_H_
+
+#include <map>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/process/process_handle.h"
+#include "base/sequence_checker.h"
+#include "base/sequenced_task_runner.h"
+#include "build/build_config.h"
+
+namespace task_management {
+
+struct ProcessDataSnapshot;
+
+// Defines sampler that will calculate resources for all processes all at once,
+// on the worker thread. Created by TaskManagerImpl on the UI thread, but used
+// mainly on a blocking pool thread.
+//
+// This exists because on Windows it is much faster to collect a group of
+// process metrics for all processes all at once using NtQuerySystemInformation
+// than to query the same data for for each process individually and because
+// some types like Idle Wakeups can only be collected this way.
+class SharedSampler : public base::RefCountedThreadSafe<SharedSampler> {
+ public:
+  explicit SharedSampler(
+      const scoped_refptr<base::SequencedTaskRunner>& blocking_pool_runner);
+
+  // Below are the types of callbacks that are invoked on the UI thread
+  // when the refresh is done on the worker thread.
+  // These callbacks are passed via RegisterCallbacks.
+  using OnIdleWakeupsCallback = base::Callback<void(int)>;
+
+  // Returns a combination of refresh flags supported by the shared sampler.
+  int64_t GetSupportedFlags() const;
+
+  // Registers task group specific callbacks.
+  void RegisterCallbacks(base::ProcessId process_id,
+                         const OnIdleWakeupsCallback& on_idle_wakeups);
+
+  // Unregisters task group specific callbacks.
+  void UnregisterCallbacks(base::ProcessId process_id);
+
+  // Refreshes the expensive process' stats (for now only idle wakeups per
+  // second) on the worker thread.
+  void Refresh(base::ProcessId process_id, int64_t refresh_flags);
+
+ private:
+  friend class base::RefCountedThreadSafe<SharedSampler>;
+  ~SharedSampler();
+
+#if defined(OS_WIN)
+  // The UI-thread callbacks in TaskGroup registered with RegisterCallbacks and
+  // to be called when refresh on the worker thread is done.
+  struct Callbacks {
+    Callbacks();
+    Callbacks(Callbacks&& other);
+    ~Callbacks();
+
+    OnIdleWakeupsCallback on_idle_wakeups;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Callbacks);
+  };
+
+  typedef std::map<base::ProcessId, Callbacks> CallbacksMap;
+
+  // Contains all results of refresh for a single process.
+  struct RefreshResult {
+    base::ProcessId process_id;
+    int idle_wakeups_per_second;
+  };
+
+  typedef std::vector<RefreshResult> RefreshResults;
+
+  // Posted on the worker thread to do the actual refresh.
+  std::unique_ptr<RefreshResults> RefreshOnWorkerThread();
+
+  // Called on UI thread when the refresh is done.
+  void OnRefreshDone(std::unique_ptr<RefreshResults> refresh_results);
+
+  // Clear cached data.
+  void ClearState();
+
+  // Used to filter process information.
+  static std::vector<base::FilePath> GetSupportedImageNames();
+  bool IsSupportedImageName(base::FilePath::StringPieceType image_name) const;
+
+  // Captures a snapshot of data for all chrome processes.
+  // Runs on the worker thread.
+  std::unique_ptr<ProcessDataSnapshot> CaptureSnapshot();
+
+  // Produce refresh results by diffing two snapshots.
+  static void MakeResultsFromTwoSnapshots(
+      const ProcessDataSnapshot& prev_snapshot,
+      const ProcessDataSnapshot& snapshot,
+      RefreshResults* results);
+
+  // Produce refresh results from one snapshot.
+  // This is used only the first time when only one snapshot is available.
+  static void MakeResultsFromSnapshot(
+      const ProcessDataSnapshot& snapshot,
+      RefreshResults* results);
+
+  // Accumulates callbacks passed from TaskGroup objects passed via
+  // RegisterCallbacks calls.
+  CallbacksMap callbacks_map_;
+
+  // Refresh flags passed via Refresh.
+  int64_t refresh_flags_;
+
+  // Snapshot of previously captured resources used to calculate the delta.
+  std::unique_ptr<ProcessDataSnapshot> previous_snapshot_;
+
+  // Size of the buffer previously used to query system information.
+  size_t previous_buffer_size_;
+
+  // Image names that CaptureSnapshot uses to filter processes.
+  const std::vector<base::FilePath> supported_image_names_;
+
+  // The specific blocking pool SequencedTaskRunner that will be used to post
+  // the refresh tasks onto serially.
+  scoped_refptr<base::SequencedTaskRunner> blocking_pool_runner_;
+
+  // To assert we're running on the correct thread.
+  base::SequenceChecker worker_pool_sequenced_checker_;
+#endif  // defined(OS_WIN)
+
+  DISALLOW_COPY_AND_ASSIGN(SharedSampler);
+};
+
+}  // namespace task_management
+
+#endif  // CHROME_BROWSER_TASK_MANAGEMENT_SAMPLING_SHARED_SAMPLER_H_