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
36HardwireCpuHelper::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
49HardwireCpuHelper::~HardwireCpuHelper()
50{
51  if (mpdecision_stopped_) {
52    RestartMpdecision();
53  }
54}
55
56bool 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
66int 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
81void 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
94void 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
103void 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