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      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 
     18 namespace 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.
     26 class 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