--- /dev/null
+/*
+ * 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.
+ */
+
+#ifndef _CENTRAL_TENDENCY_STATISTICS_H
+#define _CENTRAL_TENDENCY_STATISTICS_H
+
+#include <math.h>
+
+// Not multithread safe
+class CentralTendencyStatistics {
+
+public:
+
+ CentralTendencyStatistics() :
+ mMean(NAN), mMedian(NAN), mMinimum(INFINITY), mMaximum(-INFINITY), mN(0), mM2(0),
+ mVariance(NAN), mVarianceKnownForN(0), mStddev(NAN), mStddevKnownForN(0) { }
+
+ ~CentralTendencyStatistics() { }
+
+ // add x to the set of samples
+ void sample(double x);
+
+ // return the arithmetic mean of all samples so far
+ double mean() const { return mMean; }
+
+ // return the minimum of all samples so far
+ double minimum() const { return mMinimum; }
+
+ // return the maximum of all samples so far
+ double maximum() const { return mMaximum; }
+
+ // return the variance of all samples so far
+ double variance() const;
+
+ // return the standard deviation of all samples so far
+ double stddev() const;
+
+ // return the number of samples added so far
+ unsigned n() const { return mN; }
+
+ // reset the set of samples to be empty
+ void reset();
+
+private:
+ double mMean;
+ double mMedian;
+ double mMinimum;
+ double mMaximum;
+ unsigned mN; // number of samples so far
+ double mM2;
+
+ // cached variance, and n at time of caching
+ mutable double mVariance;
+ mutable unsigned mVarianceKnownForN;
+
+ // cached standard deviation, and n at time of caching
+ mutable double mStddev;
+ mutable unsigned mStddevKnownForN;
+
+};
+
+#endif // _CENTRAL_TENDENCY_STATISTICS_H
--- /dev/null
+This is a static library of CPU usage statistics, originally written
+for audio but most are not actually specific to audio.
+
+Requirements to be here:
+ * should be related to CPU usage statistics
+ * should be portable to host; avoid Android OS dependencies without a conditional
--- /dev/null
+/*
+ * 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.
+ */
+
+#ifndef _THREAD_CPU_USAGE_H
+#define _THREAD_CPU_USAGE_H
+
+#include <fcntl.h>
+#include <pthread.h>
+
+namespace android {
+
+// Track CPU usage for the current thread.
+// Units are in per-thread CPU ns, as reported by
+// clock_gettime(CLOCK_THREAD_CPUTIME_ID). Simple usage: for cyclic
+// threads where you want to measure the execution time of the whole
+// cycle, just call sampleAndEnable() at the start of each cycle.
+// For acyclic threads, or for cyclic threads where you want to measure/track
+// only part of each cycle, call enable(), disable(), and/or setEnabled()
+// to demarcate the region(s) of interest, and then call sample() periodically.
+// This class is not thread-safe for concurrent calls from multiple threads;
+// the methods of this class may only be called by the current thread
+// which constructed the object.
+
+class ThreadCpuUsage
+{
+
+public:
+ ThreadCpuUsage() :
+ mIsEnabled(false),
+ mWasEverEnabled(false),
+ mAccumulator(0),
+ // mPreviousTs
+ // mMonotonicTs
+ mMonotonicKnown(false)
+ {
+ (void) pthread_once(&sOnceControl, &init);
+ for (int i = 0; i < sKernelMax; ++i) {
+ mCurrentkHz[i] = (uint32_t) ~0; // unknown
+ }
+ }
+
+ ~ThreadCpuUsage() { }
+
+ // Return whether currently tracking CPU usage by current thread
+ bool isEnabled() const { return mIsEnabled; }
+
+ // Enable tracking of CPU usage by current thread;
+ // any CPU used from this point forward will be tracked.
+ // Returns the previous enabled status.
+ bool enable() { return setEnabled(true); }
+
+ // Disable tracking of CPU usage by current thread;
+ // any CPU used from this point forward will be ignored.
+ // Returns the previous enabled status.
+ bool disable() { return setEnabled(false); }
+
+ // Set the enabled status and return the previous enabled status.
+ // This method is intended to be used for safe nested enable/disabling.
+ bool setEnabled(bool isEnabled);
+
+ // Add a sample point, and also enable tracking if needed.
+ // If tracking has never been enabled, then this call enables tracking but
+ // does _not_ add a sample -- it is not possible to add a sample the
+ // first time because there is no previous point to subtract from.
+ // Otherwise, if tracking is enabled,
+ // then adds a sample for tracked CPU ns since the previous
+ // sample, or since the first call to sampleAndEnable(), enable(), or
+ // setEnabled(true). If there was a previous sample but tracking is
+ // now disabled, then adds a sample for the tracked CPU ns accumulated
+ // up until the most recent disable(), resets this accumulator, and then
+ // enables tracking. Calling this method rather than enable() followed
+ // by sample() avoids a race condition for the first sample.
+ // Returns true if the sample 'ns' is valid, or false if invalid.
+ // Note that 'ns' is an output parameter passed by reference.
+ // The caller does not need to initialize this variable.
+ // The units are CPU nanoseconds consumed by current thread.
+ bool sampleAndEnable(double& ns);
+
+ // Add a sample point, but do not
+ // change the tracking enabled status. If tracking has either never been
+ // enabled, or has never been enabled since the last sample, then log a warning
+ // and don't add sample. Otherwise, adds a sample for tracked CPU ns since
+ // the previous sample or since the first call to sampleAndEnable(),
+ // enable(), or setEnabled(true) if no previous sample.
+ // Returns true if the sample is valid, or false if invalid.
+ // Note that 'ns' is an output parameter passed by reference.
+ // The caller does not need to initialize this variable.
+ // The units are CPU nanoseconds consumed by current thread.
+ bool sample(double& ns);
+
+ // Return the elapsed delta wall clock ns since initial enable or reset,
+ // as reported by clock_gettime(CLOCK_MONOTONIC).
+ long long elapsed() const;
+
+ // Reset elapsed wall clock. Has no effect on tracking or accumulator.
+ void resetElapsed();
+
+ // Return current clock frequency for specified CPU, in kHz.
+ // You can get your CPU number using sched_getcpu(2). Note that, unless CPU affinity
+ // has been configured appropriately, the CPU number can change.
+ // Also note that, unless the CPU governor has been configured appropriately,
+ // the CPU frequency can change. And even if the CPU frequency is locked down
+ // to a particular value, that the frequency might still be adjusted
+ // to prevent thermal overload. Therefore you should poll for your thread's
+ // current CPU number and clock frequency periodically.
+ uint32_t getCpukHz(int cpuNum);
+
+private:
+ bool mIsEnabled; // whether tracking is currently enabled
+ bool mWasEverEnabled; // whether tracking was ever enabled
+ long long mAccumulator; // accumulated thread CPU time since last sample, in ns
+ struct timespec mPreviousTs; // most recent thread CPU time, valid only if mIsEnabled is true
+ struct timespec mMonotonicTs; // most recent monotonic time
+ bool mMonotonicKnown; // whether mMonotonicTs has been set
+
+ static const int MAX_CPU = 8;
+ static int sScalingFds[MAX_CPU];// file descriptor per CPU for reading scaling_cur_freq
+ uint32_t mCurrentkHz[MAX_CPU]; // current CPU frequency in kHz, not static to avoid a race
+ static pthread_once_t sOnceControl;
+ static int sKernelMax; // like MAX_CPU, but determined at runtime == cpu/kernel_max + 1
+ static void init();
+};
+
+} // namespace android
+
+#endif // _THREAD_CPU_USAGE_H
--- /dev/null
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+ CentralTendencyStatistics.cpp \
+ ThreadCpuUsage.cpp
+
+LOCAL_MODULE := libcpustats
+
+include $(BUILD_STATIC_LIBRARY)
--- /dev/null
+/*
+ * 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.
+ */
+
+#include <stdlib.h>
+
+#include <cpustats/CentralTendencyStatistics.h>
+
+void CentralTendencyStatistics::sample(double x)
+{
+ // update min and max
+ if (x < mMinimum)
+ mMinimum = x;
+ if (x > mMaximum)
+ mMaximum = x;
+ // Knuth
+ if (mN == 0) {
+ mMean = 0;
+ }
+ ++mN;
+ double delta = x - mMean;
+ mMean += delta / mN;
+ mM2 += delta * (x - mMean);
+}
+
+void CentralTendencyStatistics::reset()
+{
+ mMean = NAN;
+ mMedian = NAN;
+ mMinimum = INFINITY;
+ mMaximum = -INFINITY;
+ mN = 0;
+ mM2 = 0;
+ mVariance = NAN;
+ mVarianceKnownForN = 0;
+ mStddev = NAN;
+ mStddevKnownForN = 0;
+}
+
+double CentralTendencyStatistics::variance() const
+{
+ double variance;
+ if (mVarianceKnownForN != mN) {
+ if (mN > 1) {
+ // double variance_n = M2/n;
+ variance = mM2 / (mN - 1);
+ } else {
+ variance = NAN;
+ }
+ mVariance = variance;
+ mVarianceKnownForN = mN;
+ } else {
+ variance = mVariance;
+ }
+ return variance;
+}
+
+double CentralTendencyStatistics::stddev() const
+{
+ double stddev;
+ if (mStddevKnownForN != mN) {
+ stddev = sqrt(variance());
+ mStddev = stddev;
+ mStddevKnownForN = mN;
+ } else {
+ stddev = mStddev;
+ }
+ return stddev;
+}
--- /dev/null
+/*
+ * 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;
+
+/*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");
+ }
+
+ // open fd to each frequency per CPU
+#define FREQ_SIZE 64
+ char freq_path[FREQ_SIZE];
+#define FREQ_DIGIT 27
+ COMPILE_TIME_ASSERT_FUNCTION_SCOPE(MAX_CPU <= 10);
+ strlcpy(freq_path, "/sys/devices/system/cpu/cpu?/cpufreq/scaling_cur_freq", sizeof(freq_path));
+ int i;
+ for (i = 0; i < MAX_CPU; ++i) {
+ sScalingFds[i] = -1;
+ }
+ for (i = 0; i < sKernelMax; ++i) {
+ freq_path[FREQ_DIGIT] = i + '0';
+ fd = open(freq_path, O_RDONLY);
+ if (fd >= 0) {
+ // keep this fd until process exit
+ sScalingFds[i] = fd;
+ } else {
+ ALOGW("Can't open CPU %d", i);
+ }
+ }
+}
+
+uint32_t ThreadCpuUsage::getCpukHz(int cpuNum)
+{
+ if (cpuNum < 0 || cpuNum >= MAX_CPU) {
+ ALOGW("getCpukHz called with invalid CPU %d", cpuNum);
+ return 0;
+ }
+ int fd = sScalingFds[cpuNum];
+ if (fd < 0) {
+ ALOGW("getCpukHz called for unopened 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
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