/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "ThreadCpuUsage"
//#define LOG_NDEBUG 0
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <utils/Log.h>
#include <cpustats/ThreadCpuUsage.h>
namespace android {
bool ThreadCpuUsage::setEnabled(bool isEnabled)
{
bool wasEnabled = mIsEnabled;
// only do something if there is a change
if (isEnabled != wasEnabled) {
ALOGV("setEnabled(%d)", isEnabled);
int rc;
// enabling
if (isEnabled) {
rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &mPreviousTs);
if (rc) {
ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
isEnabled = false;
} else {
mWasEverEnabled = true;
// record wall clock time at first enable
if (!mMonotonicKnown) {
rc = clock_gettime(CLOCK_MONOTONIC, &mMonotonicTs);
if (rc) {
ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
} else {
mMonotonicKnown = true;
}
}
}
// disabling
} else {
struct timespec ts;
rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
if (rc) {
ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
} else {
long long delta = (ts.tv_sec - mPreviousTs.tv_sec) * 1000000000LL +
(ts.tv_nsec - mPreviousTs.tv_nsec);
mAccumulator += delta;
#if 0
mPreviousTs = ts;
#endif
}
}
mIsEnabled = isEnabled;
}
return wasEnabled;
}
bool ThreadCpuUsage::sampleAndEnable(double& ns)
{
bool wasEverEnabled = mWasEverEnabled;
if (enable()) {
// already enabled, so add a new sample relative to previous
return sample(ns);
} else if (wasEverEnabled) {
// was disabled, but add sample for accumulated time while enabled
ns = (double) mAccumulator;
mAccumulator = 0;
ALOGV("sampleAndEnable %.0f", ns);
return true;
} else {
// first time called
ns = 0.0;
ALOGV("sampleAndEnable false");
return false;
}
}
bool ThreadCpuUsage::sample(double &ns)
{
if (mWasEverEnabled) {
if (mIsEnabled) {
struct timespec ts;
int rc;
rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
if (rc) {
ALOGE("clock_gettime(CLOCK_THREAD_CPUTIME_ID) errno=%d", errno);
ns = 0.0;
return false;
} else {
long long delta = (ts.tv_sec - mPreviousTs.tv_sec) * 1000000000LL +
(ts.tv_nsec - mPreviousTs.tv_nsec);
mAccumulator += delta;
mPreviousTs = ts;
}
} else {
mWasEverEnabled = false;
}
ns = (double) mAccumulator;
ALOGV("sample %.0f", ns);
mAccumulator = 0;
return true;
} else {
ALOGW("Can't add sample because measurements have never been enabled");
ns = 0.0;
return false;
}
}
long long ThreadCpuUsage::elapsed() const
{
long long elapsed;
if (mMonotonicKnown) {
struct timespec ts;
int rc;
rc = clock_gettime(CLOCK_MONOTONIC, &ts);
if (rc) {
ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
elapsed = 0;
} else {
// mMonotonicTs is updated only at first enable and resetStatistics
elapsed = (ts.tv_sec - mMonotonicTs.tv_sec) * 1000000000LL +
(ts.tv_nsec - mMonotonicTs.tv_nsec);
}
} else {
ALOGW("Can't compute elapsed time because measurements have never been enabled");
elapsed = 0;
}
ALOGV("elapsed %lld", elapsed);
return elapsed;
}
void ThreadCpuUsage::resetElapsed()
{
ALOGV("resetElapsed");
if (mMonotonicKnown) {
int rc;
rc = clock_gettime(CLOCK_MONOTONIC, &mMonotonicTs);
if (rc) {
ALOGE("clock_gettime(CLOCK_MONOTONIC) errno=%d", errno);
mMonotonicKnown = false;
}
}
}
/*static*/
int ThreadCpuUsage::sScalingFds[ThreadCpuUsage::MAX_CPU];
pthread_once_t ThreadCpuUsage::sOnceControl = PTHREAD_ONCE_INIT;
int ThreadCpuUsage::sKernelMax;
pthread_mutex_t ThreadCpuUsage::sMutex = PTHREAD_MUTEX_INITIALIZER;
/*static*/
void ThreadCpuUsage::init()
{
// read the number of CPUs
sKernelMax = 1;
int fd = open("/sys/devices/system/cpu/kernel_max", O_RDONLY);
if (fd >= 0) {
#define KERNEL_MAX_SIZE 12
char kernelMax[KERNEL_MAX_SIZE];
ssize_t actual = read(fd, kernelMax, sizeof(kernelMax));
if (actual >= 2 && kernelMax[actual-1] == '\n') {
sKernelMax = atoi(kernelMax);
if (sKernelMax >= MAX_CPU - 1) {
ALOGW("kernel_max %d but MAX_CPU %d", sKernelMax, MAX_CPU);
sKernelMax = MAX_CPU;
} else if (sKernelMax < 0) {
ALOGW("kernel_max invalid %d", sKernelMax);
sKernelMax = 1;
} else {
++sKernelMax;
ALOGV("number of CPUs %d", sKernelMax);
}
} else {
ALOGW("Can't read number of CPUs");
}
(void) close(fd);
} else {
ALOGW("Can't open number of CPUs");
}
int i;
for (i = 0; i < MAX_CPU; ++i) {
sScalingFds[i] = -1;
}
}
uint32_t ThreadCpuUsage::getCpukHz(int cpuNum)
{
if (cpuNum < 0 || cpuNum >= MAX_CPU) {
ALOGW("getCpukHz called with invalid CPU %d", cpuNum);
return 0;
}
// double-checked locking idiom is not broken for atomic values such as fd
int fd = sScalingFds[cpuNum];
if (fd < 0) {
// some kernels can't open a scaling file until hot plug complete
pthread_mutex_lock(&sMutex);
fd = sScalingFds[cpuNum];
if (fd < 0) {
#define FREQ_SIZE 64
char freq_path[FREQ_SIZE];
#define FREQ_DIGIT 27
static_assert(MAX_CPU <= 10, "MAX_CPU too large");
#define FREQ_PATH "/sys/devices/system/cpu/cpu?/cpufreq/scaling_cur_freq"
strlcpy(freq_path, FREQ_PATH, sizeof(freq_path));
freq_path[FREQ_DIGIT] = cpuNum + '0';
fd = open(freq_path, O_RDONLY | O_CLOEXEC);
// keep this fd until process exit or exec
sScalingFds[cpuNum] = fd;
}
pthread_mutex_unlock(&sMutex);
if (fd < 0) {
ALOGW("getCpukHz can't open CPU %d", cpuNum);
return 0;
}
}
#define KHZ_SIZE 12
char kHz[KHZ_SIZE]; // kHz base 10
ssize_t actual = pread(fd, kHz, sizeof(kHz), (off_t) 0);
uint32_t ret;
if (actual >= 2 && kHz[actual-1] == '\n') {
ret = atoi(kHz);
} else {
ret = 0;
}
if (ret != mCurrentkHz[cpuNum]) {
if (ret > 0) {
ALOGV("CPU %d frequency %u kHz", cpuNum, ret);
} else {
ALOGW("Can't read CPU %d frequency", cpuNum);
}
mCurrentkHz[cpuNum] = ret;
}
return ret;
}
} // namespace android