1 /*
2  * Copyright 2016, Anton Blanchard, Michael Ellerman, IBM Corp.
3  * Licensed under GPLv2.
4  */
5 
6 #define _GNU_SOURCE
7 
8 #include <stdio.h>
9 #include <sys/syscall.h>
10 #include <time.h>
11 #include <unistd.h>
12 #include <linux/futex.h>
13 
14 #include "utils.h"
15 
16 #define ITERATIONS 100000000
17 
18 #define futex(A, B, C, D, E, F)	 syscall(__NR_futex, A, B, C, D, E, F)
19 
20 int test_futex(void)
21 {
22 	struct timespec ts_start, ts_end;
23 	unsigned long i = ITERATIONS;
24 
25 	clock_gettime(CLOCK_MONOTONIC, &ts_start);
26 
27 	while (i--) {
28 		unsigned int addr = 0;
29 		futex(&addr, FUTEX_WAKE, 1, NULL, NULL, 0);
30 	}
31 
32 	clock_gettime(CLOCK_MONOTONIC, &ts_end);
33 
34 	printf("time = %.6f\n", ts_end.tv_sec - ts_start.tv_sec + (ts_end.tv_nsec - ts_start.tv_nsec) / 1e9);
35 
36 	return 0;
37 }
38 
39 int main(void)
40 {
41 	return test_harness(test_futex, "futex_bench");
42 }
43