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
HardwireCpuHelper(bool perform)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
~HardwireCpuHelper()49 HardwireCpuHelper::~HardwireCpuHelper()
50 {
51 if (mpdecision_stopped_) {
52 RestartMpdecision();
53 }
54 }
55
GetMpdecisionRunning()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
GetNumCores()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
OnlineCore(int i,int onoff)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
StopMpdecision()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
RestartMpdecision()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