report bandwidth

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

1 files changed, 20 insertions, 0 deletions

diff --git a/main.c b/main.c
index 88483dd..c6f091a 100644
--- a/main.c
+++ b/main.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
+#include <time.h>
 #include <unistd.h>
 
 #include "memcpy.h"
@@ -86,10 +87,23 @@ static void do_memcpy(void *dst, const void *src)
 	}
 }
 
+#define NSEC_PER_SEC	1000000000UL
+
+static void report_bandwidth(struct timespec *start, struct timespec *end)
+{
+	double nsec = ((end->tv_sec - start->tv_sec) * NSEC_PER_SEC) +
+			(end->tv_nsec - start->tv_nsec);
+	double data = test_size * test_iterations;
+	double rate = (data / (nsec / NSEC_PER_SEC)) / GB;
+
+	printf("Rate:	%.03f GiB/sec\n", rate);
+}
+
 static void run_test(void)
 {
 	void *dst = setup_test_buffer();
 	void *src = setup_test_buffer();
+	struct timespec start, end;
 	size_t i;
 
 	printf("Iters:	%lu\n", test_iterations);
@@ -97,9 +111,15 @@ static void run_test(void)
 	printf("Source:	[%p, %p)\n", src, src + test_size);
 	printf("Dest:	[%p, %p)\n", dst, dst + test_size);
 
+	assert(!clock_gettime(CLOCK_MONOTONIC, &start));
+
 	for (i = 0; i < test_iterations; i++)
 		do_memcpy(dst, src);
 
+	assert(!clock_gettime(CLOCK_MONOTONIC, &end));
+
+	report_bandwidth(&start, &end);
+
 	destroy_test_buffer(dst);
 	destroy_test_buffer(src);
 }