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#ifndef STRACE_TESTS_TIME_ENJOYMENT_H
# define STRACE_TESTS_TIME_ENJOYMENT_H
# include <fcntl.h>
# include <sched.h>
# include <time.h>
# include <sys/types.h>
# include <sys/stat.h>
enum {
NUM_USER_ITERS_SQRT = 2000,
NUM_USER_ITERS = NUM_USER_ITERS_SQRT * NUM_USER_ITERS_SQRT,
READ_BUF_SIZE = 65536,
READ_ITER = 128,
};
static inline uint64_t
nsecs(struct timespec *ts)
{
return (uint64_t) ts->tv_sec * 1000000000 + ts->tv_nsec;
}
static inline void
enjoy_time(uint64_t cputime_limit)
{
struct timespec ts = { 0 };
volatile int dummy = 0;
/* Enjoying my user time */
for (size_t i = 0; i < NUM_USER_ITERS_SQRT; ++i) {
if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
if (nsecs(&ts) >= cputime_limit)
break;
}
for (size_t j = 0; j < NUM_USER_ITERS; ++j)
++dummy;
}
/* Enjoying my system time */
ssize_t ret;
int fd;
char buf[READ_BUF_SIZE];
while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
for (size_t i = 0; i < READ_ITER; i++) {
/* We are fine even if the calls fail. */
fd = open("/proc/self/status", O_RDONLY);
/*
* Working around "ignoring return value of 'read'
* declared with attribute 'warn_unused_result'".
*/
ret = read(fd, buf, sizeof(buf));
close(fd);
if (ret)
continue;
}
if (nsecs(&ts) >= cputime_limit * 3)
break;
sched_yield();
}
}
#endif /* !STRACE_TESTS_TIME_ENJOYMENT_H */
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