You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
47 lines
1.2 KiB
47 lines
1.2 KiB
#include <inttypes.h>
|
|
#include <sys/types.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
#define noinline __attribute__((__noinline__))
|
|
|
|
static inline uint64_t GetSystemClock() {
|
|
timespec ts;
|
|
// Assume clock_gettime() doesn't fail.
|
|
clock_gettime(CLOCK_MONOTONIC, &ts);
|
|
return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
|
|
}
|
|
|
|
constexpr int LOOP_COUNT = 100000000;
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
void noinline GlobalFunction() {
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
|
|
int main() {
|
|
GlobalFunction();
|
|
return 0;
|
|
}
|