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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 #include <stdio.h>
     19 #include <stdlib.h>
     20 #include <string.h>
     21 #include <unistd.h>
     22 #include <string>
     23 #include <sstream>
     24 #include <sys/types.h>
     25 #include <sys/wait.h>
     26 
     27 #include <android-base/logging.h>
     28 #ifdef __BIONIC__
     29 #include <android-base/properties.h>
     30 #endif
     31 
     32 #include "cpuconfig.h"
     33 
     34 #define SYSFSCPU "/sys/devices/system/cpu"
     35 
     36 HardwireCpuHelper::HardwireCpuHelper(bool perform)
     37     : mpdecision_stopped_(false)
     38 {
     39   if (perform && GetMpdecisionRunning()) {
     40     mpdecision_stopped_ = true;
     41     StopMpdecision();
     42     int ncores = GetNumCores();
     43     for (int i = 0; i < ncores; ++i) {
     44       OnlineCore(i, 1);
     45     }
     46   }
     47 }
     48 
     49 HardwireCpuHelper::~HardwireCpuHelper()
     50 {
     51   if (mpdecision_stopped_) {
     52     RestartMpdecision();
     53   }
     54 }
     55 
     56 bool HardwireCpuHelper::GetMpdecisionRunning()
     57 {
     58 #ifdef __BIONIC__
     59   return android::base::GetProperty("init.svc.mpdecision", "") == "running";
     60 #else
     61   return false;
     62 #endif
     63 }
     64 
     65 
     66 int HardwireCpuHelper::GetNumCores()
     67 {
     68   int ncores = -1;
     69   std::string possible(SYSFSCPU "/possible");
     70   FILE *fp = fopen(possible.c_str(), "re");
     71   if (fp) {
     72     unsigned lo = 0, hi = 0;
     73     if (fscanf(fp, "%u-%u", &lo, &hi) == 2) {
     74       ncores = hi - lo + 1;
     75     }
     76     fclose(fp);
     77   }
     78   return ncores;
     79 }
     80 
     81 void HardwireCpuHelper::OnlineCore(int i, int onoff)
     82 {
     83   std::stringstream ss;
     84   ss << SYSFSCPU "/cpu" << i << "/online";
     85   FILE *fp = fopen(ss.str().c_str(), "we");
     86   if (fp) {
     87     fprintf(fp, onoff ? "1\n" : "0\n");
     88     fclose(fp);
     89   } else {
     90     PLOG(WARNING) << "open failed for " << ss.str();
     91   }
     92 }
     93 
     94 void HardwireCpuHelper::StopMpdecision()
     95 {
     96 #ifdef __BIONIC__
     97   if (!android::base::SetProperty("ctl.stop", "mpdecision")) {
     98     LOG(ERROR) << "setprop ctl.stop mpdecision failed";
     99   }
    100 #endif
    101 }
    102 
    103 void HardwireCpuHelper::RestartMpdecision()
    104 {
    105 #ifdef __BIONIC__
    106   // Don't try to offline the cores we previously onlined -- let
    107   // mpdecision figure out what to do
    108 
    109   if (!android::base::SetProperty("ctl.start", "mpdecision")) {
    110     LOG(ERROR) << "setprop ctl.start mpdecision failed";
    111   }
    112 #endif
    113 }
    114