Added support for passing sample_period as command line

NOTE: To reduce number of overflow occurance while testing with
perf hw counter, we can tune sample_period value as parameter.

Signed-off-by: Yogesh Tillu <yogesh.tillu@linaro.org>
Reviewed-by: Anders Roxell <anders.roxell@linaro.org>

1 files changed, 10 insertions, 7 deletions

diff --git a/perf_rc_mmap.c b/perf_rc_mmap.c
index 34dab28..57767be 100644
--- a/perf_rc_mmap.c
+++ b/perf_rc_mmap.c
@@ -37,7 +37,7 @@ static void sigio_handler(int signo, siginfo_t *info, void *uc)
 	overflow = overflow + 1;
 }
 
-static int counter_init(unsigned int counter)
+static int counter_init(unsigned int counter,long unsigned int sample)
 {
 	static struct perf_event_attr attr;
 	static struct sigaction sigio;
@@ -53,8 +53,7 @@ static int counter_init(unsigned int counter)
 	if (sigaction(SIGIO, &sigio, NULL) == -1) {
 		printf("Error: SIGIO signal handler %s\n",strerror(errno));
 	}
-
-	attr.sample_period = 1000000;
+	attr.sample_period = sample;
 	attr.sample_type = PERF_SAMPLE_IP;
 	attr.wakeup_events = 1;
 	attr.config = counter;
@@ -127,8 +126,9 @@ void print_usage(char *argv)
 	"Refer to 'enum perf_hw_id'[file <linux/perf_event.h>] for hw\n"
 	"counter enum value in range of 0 to PERF_COUNT_HW_MAX\n"
 	"-n\t Length size array will implement busyloop\n"
+	"-s\t Sample period [> 1000000 samples]\n"
 	"e.g.\n"
-	"\t%s -c 0 -n 64\n", argv, argv, argv);
+	"\t%s -c 0 -n 64 -s 1000000\n", argv, argv, argv);
 }
 
 int main(int ac, char *argv[])
@@ -139,9 +139,9 @@ int main(int ac, char *argv[])
 	int len = -1, cnt = -1;
 	int i, pre_loop_res, post_loop_res, sum = 0;
 	void *addr; /* mmaped address */
-	unsigned long start_count, stop_count;
+	unsigned long start_count, stop_count, s_period=1000000;
 
-	while ((option = getopt(ac, argv, "c:n:")) != -1) {
+	while ((option = getopt(ac, argv, "c:n:s:")) != -1) {
 		switch (option) {
 		case 'c':
 			cnt = atoi(optarg);
@@ -149,6 +149,9 @@ int main(int ac, char *argv[])
 		case 'n':
 			len = atoi(optarg);
 			break;
+		case 's':
+			s_period = atoi(optarg);
+			break;
 		default:
 			print_usage(argv[0]);
 			exit(EXIT_FAILURE);
@@ -160,7 +163,7 @@ int main(int ac, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
-	if (counter_init(cnt) < 0) {
+	if (counter_init(cnt, s_period) < 0) {
 		printf("Error: Counter Invalid\n");
 		print_usage(argv[0]);
 		exit(EXIT_FAILURE);