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      1 /*
      2 **
      3 ** Copyright 2015, The Android Open Source Project
      4 **
      5 ** Licensed under the Apache License, Version 2.0 (the "License");
      6 ** you may not use this file except in compliance with the License.
      7 ** You may obtain a copy of the License at
      8 **
      9 **     http://www.apache.org/licenses/LICENSE-2.0
     10 **
     11 ** Unless required by applicable law or agreed to in writing, software
     12 ** distributed under the License is distributed on an "AS IS" BASIS,
     13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14 ** See the License for the specific language governing permissions and
     15 ** limitations under the License.
     16 */
     17 
     18 //
     19 // Helper class to perform cpu setup (if needed) prior to a profile collection.
     20 //
     21 class HardwireCpuHelper {
     22  public:
     23 
     24   // The constructor for this class checks to see if the 'mpdecision'
     25   // service is running; if so (and if 'perform' is TRUE), then it
     26   // disables the service and on-lines all of the available cores/cpus
     27   // (anything listed in /sys/devices/system/cpu/possible). The
     28   // destructor will re-enable the mpdecision service if it was
     29   // previously disabled.
     30   HardwireCpuHelper(bool perform);
     31   virtual ~HardwireCpuHelper();
     32 
     33  private:
     34   bool mpdecision_stopped_;
     35 
     36   // Collect the number of available cpus/cores from /sys/devices/system/cpu/possible
     37   int GetNumCores();
     38 
     39   // Returns TRUE if the system service 'mpdecision' is running
     40   bool GetMpdecisionRunning();
     41 
     42   // Online/offline the specified cpu
     43   void OnlineCore(int whichCore, int onoff);
     44 
     45   // Enable/disable the mpdecision service via the equivalent of
     46   //   setprop ctl.start mpdecision
     47   //   setprop ctl.stop mpdecision
     48   void StopMpdecision();
     49   void RestartMpdecision();
     50 };
     51