Add parser for new cpu freq file

chrome/browser/chromeos/power/cpu_data_collector.h

 // Copyright 2014 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_POWER_CPU_DATA_COLLECTOR_H_
 #define CHROME_BROWSER_CHROMEOS_POWER_CPU_DATA_COLLECTOR_H_
 
 #include <stdint.h>
 
 #include <deque>
 #include <map>
 #include <string>
 #include <vector>
 
+#include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 
 namespace chromeos {
 
 // A class to sample CPU idle state occupancy and freq state occupancy.
 // Collects raw data from sysfs and does not convert it to percentage
 // occupancy. As CPUs can be offline at times, or the system can be suspended at
 // other times, it is best for the consumer of this data to calculate percentage
 // occupancy information using suspend time data from
 // PowerDataCollector::system_resumed_data.
 class CpuDataCollector {
  public:
   struct StateOccupancySample {
     StateOccupancySample();
     StateOccupancySample(const StateOccupancySample& other);
     ~StateOccupancySample();
 
     // The time when the data was sampled.
     base::Time time;
 
     // Indicates whether the CPU is online.
     bool cpu_online;
 
     // A mapping from a CPU state to time spent in that state in milliseconds.

[Daniel Erat, 2017/05/03 23:39:35]

nit: remove "in milliseconds" from this comment now

[weidongg, 2017/05/03 23:53:26]

Done.

     // For idle state samples, the name of the state at index i in this vector
     // is the name at index i in the vector returned by cpu_idle_state_names().
     // Similarly, for freq state occupancy, similar information is in the vector
     // returned by cpu_freq_state_names().
-    std::vector<int64_t> time_in_state;
+    std::vector<base::TimeDelta> time_in_state;
   };
 
   typedef std::deque<StateOccupancySample> StateOccupancySampleDeque;
 
   const std::vector<std::string>& cpu_idle_state_names() const {
     return cpu_idle_state_names_;
   }
 
   const std::vector<StateOccupancySampleDeque>& cpu_idle_state_data() const {
     return cpu_idle_state_data_;
   }
 
   const std::vector<std::string>& cpu_freq_state_names() const {
     return cpu_freq_state_names_;
   }
 
   const std::vector<StateOccupancySampleDeque>& cpu_freq_state_data() const {
     return cpu_freq_state_data_;
   }
 
   CpuDataCollector();
   ~CpuDataCollector();
 
   // Starts a repeating timer which periodically runs a callback to collect
   // CPU state occupancy samples.
   void Start();
 
+  // Read CPU frequency data of a specific CPU from the file in |path| and fill
+  // |cpu_freq_state_names| and |freq_sample| with the data.
+  // Sample file looks like:
+  // 126000 223344
+  // 216000 93495
+  // ...
+  // 1800000 321907
+  static bool ReadCpuFreqTimeInState(
+      const base::FilePath& path,
+      std::vector<std::string>* cpu_freq_state_names,
+      CpuDataCollector::StateOccupancySample* freq_sample);
+
+  // Read CPU frequency data of all CPUs from the file in |path| and fill
+  // |cpu_freq_state_names| and |freq_samples| with the data. |cpu_count| is the
+  // number of possible CPUs on the system. Note that |freq_samples| is not
+  // empty and sample at index i in |freq_samples| corresponds to the freq state
+  // information of the i-th CPU. |cpu_online| of each sample must be set before
+  // calling this function.
+  // Sample file looks like:
+  // freq   cpu0    cpu1
+  // 126000   223344    223311
+  // 216000   93495   93450
+  // ...
+  // 1800000    321907    331897
+  static bool ReadCpuFreqAllTimeInState(
+      int cpu_count,
+      const base::FilePath& path,
+      std::vector<std::string>* cpu_freq_state_names,
+      std::vector<CpuDataCollector::StateOccupancySample>* freq_samples);
+
  private:
   // Posts callbacks to the blocking pool which collect CPU state occupancy
   // samples from the sysfs.
   void PostSampleCpuState();
 
   // This function commits the CPU count and samples read by
   // SampleCpuStateAsync to |cpu_idle_state_data_| and
   // |cpu_freq_state_data_|. Since UI is the consumer of CPU idle and freq data,
   // this function should run on the UI thread.
   void SaveCpuStateSamplesOnUIThread(
@@ skipping 23 matching lines @@
   // hence should be read/written to only from the blocking pool.
   int cpu_count_;
 
   base::WeakPtrFactory<CpuDataCollector> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(CpuDataCollector);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_POWER_CPU_DATA_COLLECTOR_H_