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Diffstat (limited to 'media/libcpustats/ThreadCpuUsage.cpp')
| -rw-r--r-- | media/libcpustats/ThreadCpuUsage.cpp | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/media/libcpustats/ThreadCpuUsage.cpp b/media/libcpustats/ThreadCpuUsage.cpp new file mode 100644 index 0000000..637402a --- /dev/null +++ b/media/libcpustats/ThreadCpuUsage.cpp @@ -0,0 +1,255 @@ +/* + * 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 <time.h> + +#include <utils/Debug.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 ret; + 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 + COMPILE_TIME_ASSERT_FUNCTION_SCOPE(MAX_CPU <= 10); +#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 |