1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "ThreadCpuUsage"
18 //#define LOG_NDEBUG 0
19
20 #include <errno.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <time.h>
24
25 #include <utils/Log.h>
26
27 #include <cpustats/ThreadCpuUsage.h>
28
29 namespace android {
30
setEnabled(bool isEnabled)31 bool ThreadCpuUsage::setEnabled(bool isEnabled)
32 {
33 bool wasEnabled = mIsEnabled;
34 // only do something if there is a change
35 if (isEnabled != wasEnabled) {
36 ALOGV("setEnabled(%d)", isEnabled);
37 int rc;
38 // enabling
39 if (isEnabled) {
40 rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &mPreviousTs);
41 if (rc) {
42 ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
43 isEnabled = false;
44 } else {
45 mWasEverEnabled = true;
46 // record wall clock time at first enable
47 if (!mMonotonicKnown) {
48 rc = clock_gettime(CLOCK_MONOTONIC, &mMonotonicTs);
49 if (rc) {
50 ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
51 } else {
52 mMonotonicKnown = true;
53 }
54 }
55 }
56 // disabling
57 } else {
58 struct timespec ts;
59 rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
60 if (rc) {
61 ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
62 } else {
63 long long delta = (ts.tv_sec - mPreviousTs.tv_sec) * 1000000000LL +
64 (ts.tv_nsec - mPreviousTs.tv_nsec);
65 mAccumulator += delta;
66 #if 0
67 mPreviousTs = ts;
68 #endif
69 }
70 }
71 mIsEnabled = isEnabled;
72 }
73 return wasEnabled;
74 }
75
sampleAndEnable(double & ns)76 bool ThreadCpuUsage::sampleAndEnable(double& ns)
77 {
78 bool wasEverEnabled = mWasEverEnabled;
79 if (enable()) {
80 // already enabled, so add a new sample relative to previous
81 return sample(ns);
82 } else if (wasEverEnabled) {
83 // was disabled, but add sample for accumulated time while enabled
84 ns = (double) mAccumulator;
85 mAccumulator = 0;
86 ALOGV("sampleAndEnable %.0f", ns);
87 return true;
88 } else {
89 // first time called
90 ns = 0.0;
91 ALOGV("sampleAndEnable false");
92 return false;
93 }
94 }
95
sample(double & ns)96 bool ThreadCpuUsage::sample(double &ns)
97 {
98 if (mWasEverEnabled) {
99 if (mIsEnabled) {
100 struct timespec ts;
101 int rc;
102 rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
103 if (rc) {
104 ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
105 ns = 0.0;
106 return false;
107 } else {
108 long long delta = (ts.tv_sec - mPreviousTs.tv_sec) * 1000000000LL +
109 (ts.tv_nsec - mPreviousTs.tv_nsec);
110 mAccumulator += delta;
111 mPreviousTs = ts;
112 }
113 } else {
114 mWasEverEnabled = false;
115 }
116 ns = (double) mAccumulator;
117 ALOGV("sample %.0f", ns);
118 mAccumulator = 0;
119 return true;
120 } else {
121 ALOGW("Can't add sample because measurements have never been enabled");
122 ns = 0.0;
123 return false;
124 }
125 }
126
elapsed() const127 long long ThreadCpuUsage::elapsed() const
128 {
129 long long elapsed;
130 if (mMonotonicKnown) {
131 struct timespec ts;
132 int rc;
133 rc = clock_gettime(CLOCK_MONOTONIC, &ts);
134 if (rc) {
135 ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
136 elapsed = 0;
137 } else {
138 // mMonotonicTs is updated only at first enable and resetStatistics
139 elapsed = (ts.tv_sec - mMonotonicTs.tv_sec) * 1000000000LL +
140 (ts.tv_nsec - mMonotonicTs.tv_nsec);
141 }
142 } else {
143 ALOGW("Can't compute elapsed time because measurements have never been enabled");
144 elapsed = 0;
145 }
146 ALOGV("elapsed %lld", elapsed);
147 return elapsed;
148 }
149
resetElapsed()150 void ThreadCpuUsage::resetElapsed()
151 {
152 ALOGV("resetElapsed");
153 if (mMonotonicKnown) {
154 int rc;
155 rc = clock_gettime(CLOCK_MONOTONIC, &mMonotonicTs);
156 if (rc) {
157 ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
158 mMonotonicKnown = false;
159 }
160 }
161 }
162
163 /*static*/
164 int ThreadCpuUsage::sScalingFds[ThreadCpuUsage::MAX_CPU];
165 pthread_once_t ThreadCpuUsage::sOnceControl = PTHREAD_ONCE_INIT;
166 int ThreadCpuUsage::sKernelMax;
167 pthread_mutex_t ThreadCpuUsage::sMutex = PTHREAD_MUTEX_INITIALIZER;
168
169 /*static*/
init()170 void ThreadCpuUsage::init()
171 {
172 // read the number of CPUs
173 sKernelMax = 1;
174 int fd = open("/sys/devices/system/cpu/kernel_max", O_RDONLY);
175 if (fd >= 0) {
176 #define KERNEL_MAX_SIZE 12
177 char kernelMax[KERNEL_MAX_SIZE];
178 ssize_t actual = read(fd, kernelMax, sizeof(kernelMax));
179 if (actual >= 2 && kernelMax[actual-1] == '\n') {
180 sKernelMax = atoi(kernelMax);
181 if (sKernelMax >= MAX_CPU - 1) {
182 ALOGW("kernel_max %d but MAX_CPU %d", sKernelMax, MAX_CPU);
183 sKernelMax = MAX_CPU;
184 } else if (sKernelMax < 0) {
185 ALOGW("kernel_max invalid %d", sKernelMax);
186 sKernelMax = 1;
187 } else {
188 ++sKernelMax;
189 ALOGV("number of CPUs %d", sKernelMax);
190 }
191 } else {
192 ALOGW("Can't read number of CPUs");
193 }
194 (void) close(fd);
195 } else {
196 ALOGW("Can't open number of CPUs");
197 }
198 int i;
199 for (i = 0; i < MAX_CPU; ++i) {
200 sScalingFds[i] = -1;
201 }
202 }
203
getCpukHz(int cpuNum)204 uint32_t ThreadCpuUsage::getCpukHz(int cpuNum)
205 {
206 if (cpuNum < 0 || cpuNum >= MAX_CPU) {
207 ALOGW("getCpukHz called with invalid CPU %d", cpuNum);
208 return 0;
209 }
210 // double-checked locking idiom is not broken for atomic values such as fd
211 int fd = sScalingFds[cpuNum];
212 if (fd < 0) {
213 // some kernels can't open a scaling file until hot plug complete
214 pthread_mutex_lock(&sMutex);
215 fd = sScalingFds[cpuNum];
216 if (fd < 0) {
217 #define FREQ_SIZE 64
218 char freq_path[FREQ_SIZE];
219 #define FREQ_DIGIT 27
220 static_assert(MAX_CPU <= 10, "MAX_CPU too large");
221 #define FREQ_PATH "/sys/devices/system/cpu/cpu?/cpufreq/scaling_cur_freq"
222 strlcpy(freq_path, FREQ_PATH, sizeof(freq_path));
223 freq_path[FREQ_DIGIT] = cpuNum + '0';
224 fd = open(freq_path, O_RDONLY | O_CLOEXEC);
225 // keep this fd until process exit or exec
226 sScalingFds[cpuNum] = fd;
227 }
228 pthread_mutex_unlock(&sMutex);
229 if (fd < 0) {
230 ALOGW("getCpukHz can't open CPU %d", cpuNum);
231 return 0;
232 }
233 }
234 #define KHZ_SIZE 12
235 char kHz[KHZ_SIZE]; // kHz base 10
236 ssize_t actual = pread(fd, kHz, sizeof(kHz), (off_t) 0);
237 uint32_t ret;
238 if (actual >= 2 && kHz[actual-1] == '\n') {
239 ret = atoi(kHz);
240 } else {
241 ret = 0;
242 }
243 if (ret != mCurrentkHz[cpuNum]) {
244 if (ret > 0) {
245 ALOGV("CPU %d frequency %u kHz", cpuNum, ret);
246 } else {
247 ALOGW("Can't read CPU %d frequency", cpuNum);
248 }
249 mCurrentkHz[cpuNum] = ret;
250 }
251 return ret;
252 }
253
254 } // namespace android
255