From 97248c9681a5b08ff4ee8d8b55e4d94d1f41b4d0 Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Sun, 2 Feb 2025 20:03:44 +0100
Subject: [PATCH] Add a time measuring lib to copy/paste.
---
c/time-measuring.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
create mode 100644 c/time-measuring.c
diff --git a/c/time-measuring.c b/c/time-measuring.c
new file mode 100644
index 0000000..60ca334
--- /dev/null
+++ b/c/time-measuring.c
@@ -0,0 +1,57 @@
+#include <stdio.h>
+//#include <sys/time.h>
+#include <time.h>
+#include <stdlib.h>
+
+#define BILLION 1000000000L
+#define MILLION 1000000L
+#define THOUSAND 1000L
+
+void get_time_ts(struct timespec *t0) {
+ if (clock_gettime(CLOCK_REALTIME, t0) == -1) {
+ perror("clock_gettime");
+ exit(1);
+ }
+}
+
+long long duration_ns(struct timespec t0, struct timespec t1) {
+ return ((t1.tv_sec - t0.tv_sec)*BILLION) + (t1.tv_nsec - t0.tv_nsec);
+}
+
+void print_time_ns(long long time) {
+ printf("%llds %lldms %lldµ %lldns\n"
+ , time/BILLION
+ , (time/MILLION)%THOUSAND
+ , (time/THOUSAND)%THOUSAND
+ , time%THOUSAND
+ );
+}
+
+int main (int argc, char** argv) {
+ struct timespec t0, t1;
+
+ get_time_ts(&t0);
+
+ int i = 0;
+ while (i < 10000) { i++; }
+
+ get_time_ts(&t1);
+
+ long long time = duration_ns(t0, t1);
+
+ print_time_ns(time);
+
+ return 0;
+}
+
+/* // For limited precision: timeval structure + gettimeofday function.
+ struct timeval t0, t1;
+
+ gettimeofday (&t0, NULL);
+ int i = 0;
+ while (i < 10000) { i++; }
+
+ gettimeofday (&t1, NULL);
+
+ printf("%ld ms\n", (t1.tv_sec - t0.tv_sec)*BILLION + (t1.tv_usec - t0.tv_usec));
+*/