| #include <jni.h> |
| #include <pthread.h> |
| #include <stdlib.h> |
| #include <time.h> |
| #include <string> |
| |
| #define noinline __attribute__((__noinline__)) |
| extern "C" JNIEXPORT jstring JNICALL |
| Java_simpleperf_example_cpp_MainActivity_stringFromJNI( |
| JNIEnv* env, |
| jobject /* this */) { |
| std::string hello = "Hello from C++"; |
| return env->NewStringUTF(hello.c_str()); |
| } |
| |
| static void ThrowErrnoException(JNIEnv* env, const char* function_name, int err) { |
| jclass cls = env->FindClass("android/system/ErrnoException"); |
| if (cls == nullptr) { |
| return; |
| } |
| jmethodID cid = env->GetMethodID(cls, "<init>", "(Ljava/lang/String;I)V"); |
| if (cid == nullptr) { |
| return; |
| } |
| jstring msg = env->NewStringUTF(function_name); |
| if (msg == nullptr) { |
| return; |
| } |
| jthrowable obj = (jthrowable)env->NewObject(cls, cid, msg, err); |
| if (obj == nullptr) { |
| return; |
| } |
| env->Throw(obj); |
| } |
| |
| int CallFunction(int a) { |
| return a + atoi("1"); |
| } |
| |
| static void* BusyLoopThread(void*) { |
| volatile int i = 0; |
| while (true) { |
| i = CallFunction(i); |
| } |
| return nullptr; |
| } |
| |
| extern "C" |
| JNIEXPORT void JNICALL |
| Java_simpleperf_example_cpp_MainActivity_createBusyThreadFromJNI( |
| JNIEnv *env, |
| jobject /* this */) { |
| pthread_t thread; |
| int ret = pthread_create(&thread, nullptr, BusyLoopThread, nullptr); |
| if (ret) { |
| ThrowErrnoException(env, "pthread_create", ret); |
| return; |
| } |
| } |
| |
| static inline uint64_t GetSystemClock() { |
| timespec ts; |
| clock_gettime(CLOCK_MONOTONIC, &ts); |
| return ts.tv_sec * 1000000000ULL + ts.tv_nsec; |
| } |
| |
| constexpr int LOOP_COUNT = 100000000; |
| static uint64_t noinline RunFunction() { |
| uint64_t start_time_in_ns = GetSystemClock(); |
| for (volatile int i = 0; i < LOOP_COUNT; ++i) { |
| } |
| return GetSystemClock() - start_time_in_ns; |
| } |
| |
| static uint64_t noinline SleepFunction(unsigned long long sleep_time_in_ns) { |
| uint64_t start_time_in_ns = GetSystemClock(); |
| struct timespec req; |
| req.tv_sec = sleep_time_in_ns / 1000000000; |
| req.tv_nsec = sleep_time_in_ns % 1000000000; |
| nanosleep(&req, nullptr); |
| return GetSystemClock() - start_time_in_ns; |
| } |
| |
| static void* SleepThread(void*) { |
| pthread_setname_np(pthread_self(), "SleepThread"); |
| uint64_t total_sleep_time_in_ns = 0; |
| uint64_t total_run_time_in_ns = 0; |
| while (true) { |
| total_run_time_in_ns += RunFunction(); |
| if (total_sleep_time_in_ns < total_run_time_in_ns) { |
| total_sleep_time_in_ns += SleepFunction(total_run_time_in_ns - total_sleep_time_in_ns); |
| } |
| } |
| } |
| |
| extern "C" |
| JNIEXPORT void JNICALL |
| Java_simpleperf_example_cpp_SleepActivity_createSleepThreadFromJNI( |
| JNIEnv *env, |
| jobject /* this */) { |
| pthread_t thread; |
| int ret = pthread_create(&thread, nullptr, SleepThread, nullptr); |
| if (ret) { |
| ThrowErrnoException(env, "pthread_create", ret); |
| return; |
| } |
| } |
| |
| extern "C" |
| JNIEXPORT int JNICALL |
| Java_simpleperf_example_cpp_MixActivity_callFunction( |
| JNIEnv *env, |
| jobject /* this */, |
| int a) { |
| return CallFunction(a); |
| } |