chap3

bac2/os/chap3/ex5.c

@@ -0,0 +1,29 @@
+#include <sys/time.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+
+#define printvi(X) printf("%s = %d\n", #X, X);
+#define printvf(X) printf("%s = %lld\n", #X, X);
+
+typedef struct timespec timespec_t;
+
+timespec_t start, end, s = {0, 1};
+
+long long int dtime(timespec_t *start, timespec_t *end){
+	return (end->tv_sec - start->tv_sec) * 1e9 + end->tv_nsec - start->tv_nsec;
+}
+
+int main(void)
+{
+	FILE* fd = fopen("plot", "w");
+	long long int time, time_sum;
+	for (int i = 0; i < 10000; ++i) {
+		clock_gettime(CLOCK_REALTIME, &start);
+		nanosleep(&s, NULL);
+		clock_gettime(CLOCK_REALTIME, &end);
+		time = dtime(&start, &end);
+		time_sum += time;
+		fprintf(fd, "%d	%lld\n", i, time);
+	}
+}