1// Copyright 2014 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#ifndef CHROME_BROWSER_CHROMEOS_POWER_CPU_DATA_COLLECTOR_H_
6#define CHROME_BROWSER_CHROMEOS_POWER_CPU_DATA_COLLECTOR_H_
7
8#include <deque>
9#include <map>
10#include <string>
11#include <vector>
12
13#include "base/basictypes.h"
14#include "base/memory/weak_ptr.h"
15#include "base/time/time.h"
16#include "base/timer/timer.h"
17
18namespace chromeos {
19
20// A class to sample CPU idle state occupancy and freq state occupancy.
21// Collects raw data from sysfs and does not convert it to percentage
22// occupancy. As CPUs can be offline at times, or the system can be suspended at
23// other times, it is best for the consumer of this data to calculate percentage
24// occupancy information using suspend time data from
25// PowerDataCollector::system_resumed_data.
26class CpuDataCollector {
27 public:
28  struct StateOccupancySample {
29    StateOccupancySample();
30    ~StateOccupancySample();
31
32    // The time when the data was sampled.
33    base::Time time;
34
35    // Indicates whether the CPU is online.
36    bool cpu_online;
37
38    // A mapping from a CPU state to time spent in that state in milliseconds.
39    // For idle state samples, the name of the state at index i in this vector
40    // is the name at index i in the vector returned by cpu_idle_state_names().
41    // Similarly, for freq state occupancy, similar information is in the vector
42    // returned by cpu_freq_state_names().
43    std::vector<int64> time_in_state;
44  };
45
46  typedef std::deque<StateOccupancySample> StateOccupancySampleDeque;
47
48  const std::vector<std::string>& cpu_idle_state_names() const {
49    return cpu_idle_state_names_;
50  }
51
52  const std::vector<StateOccupancySampleDeque>& cpu_idle_state_data() const {
53    return cpu_idle_state_data_;
54  }
55
56  const std::vector<std::string>& cpu_freq_state_names() const {
57    return cpu_freq_state_names_;
58  }
59
60  const std::vector<StateOccupancySampleDeque>& cpu_freq_state_data() const {
61    return cpu_freq_state_data_;
62  }
63
64  CpuDataCollector();
65  ~CpuDataCollector();
66
67  // Starts a repeating timer which periodically runs a callback to collect
68  // CPU state occupancy samples.
69  void Start();
70
71 private:
72  // Posts callbacks to the blocking pool which collect CPU state occupancy
73  // samples from the sysfs.
74  void PostSampleCpuState();
75
76  // This function commits the CPU count and samples read by
77  // SampleCpuStateOnBlockingPool to |cpu_idle_state_data_| and
78  // |cpu_freq_state_data_|. Since UI is the consumer of CPU idle and freq data,
79  // this function should run on the UI thread.
80  void SaveCpuStateSamplesOnUIThread(
81      const int* cpu_count,
82      const std::vector<std::string>* cpu_idle_state_names,
83      const std::vector<StateOccupancySample>* idle_samples,
84      const std::vector<std::string>* cpu_freq_state_names,
85      const std::vector<StateOccupancySample>* freq_samples);
86
87  base::RepeatingTimer<CpuDataCollector> timer_;
88
89  // Names of the idle states.
90  std::vector<std::string> cpu_idle_state_names_;
91
92  // The deque at index <i> in the vector corresponds to the idle state
93  // occupancy data of CPU<i>.
94  std::vector<StateOccupancySampleDeque> cpu_idle_state_data_;
95
96  // Names of the freq states.
97  std::vector<std::string> cpu_freq_state_names_;
98
99  // The deque at index <i> in the vector corresponds to the frequency state
100  // occupancy data of CPU<i>.
101  std::vector<StateOccupancySampleDeque> cpu_freq_state_data_;
102
103  // The number of CPUs on the system. This value is read from the sysfs, and
104  // hence should be read/written to only from the blocking pool.
105  int cpu_count_;
106
107  base::WeakPtrFactory<CpuDataCollector> weak_ptr_factory_;
108  DISALLOW_COPY_AND_ASSIGN(CpuDataCollector);
109};
110
111}  // namespace chromeos
112
113#endif  // CHROME_BROWSER_CHROMEOS_POWER_CPU_DATA_COLLECTOR_H_
114