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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 <cutils/properties.h>
     28 
     29 #include "cpuconfig.h"
     30 #include "perfprofdutils.h"
     31 
     32 #define SYSFSCPU "/sys/devices/system/cpu"
     33 
     34 HardwireCpuHelper::HardwireCpuHelper(bool perform)
     35     : mpdecision_stopped_(false)
     36 {
     37   if (perform && GetMpdecisionRunning()) {
     38     mpdecision_stopped_ = true;
     39     StopMpdecision();
     40     int ncores = GetNumCores();
     41     for (int i = 0; i < ncores; ++i) {
     42       OnlineCore(i, 1);
     43     }
     44   }
     45 }
     46 
     47 HardwireCpuHelper::~HardwireCpuHelper()
     48 {
     49   if (mpdecision_stopped_) {
     50     RestartMpdecision();
     51   }
     52 }
     53 
     54 bool HardwireCpuHelper::GetMpdecisionRunning()
     55 {
     56   char propBuf[PROPERTY_VALUE_MAX];
     57   property_get("init.svc.mpdecision", propBuf, "");
     58   return strcmp(propBuf, "running") == 0;
     59 }
     60 
     61 
     62 int HardwireCpuHelper::GetNumCores()
     63 {
     64   int ncores = -1;
     65   std::string possible(SYSFSCPU "/possible");
     66   FILE *fp = fopen(possible.c_str(), "re");
     67   if (fp) {
     68     unsigned lo = 0, hi = 0;
     69     if (fscanf(fp, "%u-%u", &lo, &hi) == 2) {
     70       ncores = hi - lo + 1;
     71     }
     72     fclose(fp);
     73   }
     74   return ncores;
     75 }
     76 
     77 void HardwireCpuHelper::OnlineCore(int i, int onoff)
     78 {
     79   std::stringstream ss;
     80   ss << SYSFSCPU "/cpu" << i << "/online";
     81   FILE *fp = fopen(ss.str().c_str(), "we");
     82   if (fp) {
     83     fprintf(fp, onoff ? "1\n" : "0\n");
     84     fclose(fp);
     85   } else {
     86     W_ALOGW("open failed for %s", ss.str().c_str());
     87   }
     88 }
     89 
     90 void HardwireCpuHelper::StopMpdecision()
     91 {
     92   if (property_set("ctl.stop", "mpdecision")) {
     93     W_ALOGE("setprop ctl.stop mpdecision failed");
     94   }
     95 }
     96 
     97 void HardwireCpuHelper::RestartMpdecision()
     98 {
     99   // Don't try to offline the cores we previously onlined -- let
    100   // mpdecision figure out what to do
    101 
    102   if (property_set("ctl.start", "mpdecision")) {
    103     W_ALOGE("setprop ctl.start mpdecision failed");
    104   }
    105 }
    106