perf_ev_open:

Added support for all perf hw counter
Added getopt support for argument
Added print_usage for help

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

1 files changed, 70 insertions, 22 deletions

diff --git a/perf_ev_open.c b/perf_ev_open.c
index 3550bfd..9b06586 100644
--- a/perf_ev_open.c
+++ b/perf_ev_open.c
@@ -16,21 +16,27 @@
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <linux/perf_event.h>
+#include <getopt.h>
 
 static int fddev = -1;
-__attribute__((constructor)) static void
-init(void)
+
+static int  counter_init(unsigned int counter)
 {
 	static struct perf_event_attr attr;
 	attr.type = PERF_TYPE_HARDWARE;
-	attr.config = PERF_COUNT_HW_CPU_CYCLES;
+	if (counter < 0 || counter > PERF_COUNT_HW_MAX)
+		return -1;
+
+	attr.config = counter;
 	fddev = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
-}
+	if (fddev == -1) {
+		fprintf(stderr,
+			"Error opening perf_event_open for counter %llx\n"
+			, attr.config);
+		return -1;
+	}
 
-__attribute__((destructor)) static void
-fini(void)
-{
-	close(fddev);
+	return 0;
 }
 
 static inline long long cpucycles(void)
@@ -38,10 +44,11 @@ static inline long long cpucycles(void)
 	long long result = 0;
 	if (read(fddev, &result, sizeof(result)) < sizeof(result))
 		return 0;
+
 	return result;
 }
 
-/* Simple loop body to keep things interested. Make sure it gets inlined. */
+/* loop body to keep things interested. Make sure it gets inlined. */
 static inline int
 loop(int* __restrict__ a, int* __restrict__ b, int n)
 {
@@ -50,22 +57,56 @@ loop(int* __restrict__ a, int* __restrict__ b, int n)
 	for (i = 0; i < n; ++i)
 		if (a[i] > b[i])
 			sum += a[i] + 5;
+
 	return sum;
 }
 
-int main(int ac, char **av)
+void print_usage(char *argv)
+{
+	printf("Usage: %s -c perf_hw_counter -n length\n"
+	"%s - read perf hardware counters from userspace\n\n"
+	"-c\t perf_hw_counter is enum value of hw counter for platform\n"
+	"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"
+	"e.g.\n"
+	"\t%s -c 0 -n 64\n", argv, argv, argv);
+}
+
+int main(int ac, char *argv[])
 {
 	long long time_start = 0;
 	long long time_end   = 0;
-
+	int option = 0;
+	int len = -1, cnt = -1;
 	int *a  = NULL;
 	int *b  = NULL;
-	int len = 0;
-	int i, sum = 0;
-	if (ac != 2)
-		return -1;
-	len = atoi(av[1]);
-	printf("%s: len = %d\n", av[0], len);
+	int i, result, sum = 0;
+
+	while ((option = getopt(ac, argv, "c:n:")) != -1) {
+		switch (option) {
+		case 'c':
+			cnt = atoi(optarg);
+			break;
+		case 'n':
+			len = atoi(optarg);
+			break;
+		default:
+			print_usage(argv[0]);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (len == -1 || cnt == -1) {
+		print_usage(argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (counter_init(cnt) < 0) {
+		printf("Error: Counter Invalid\n");
+		print_usage(argv[0]);
+		exit(EXIT_FAILURE);
+	}
 
 	a = malloc(len*sizeof(*a));
 	b = malloc(len*sizeof(*b));
@@ -74,7 +115,7 @@ int main(int ac, char **av)
 		a[i] = i+128;
 		b[i] = i+64;
 	}
-	printf("%s: beginning loop\n", av[0]);
+
 	time_start = time_end = 0;
 	/* --------------------Critical section-------------- */
 	time_start = cpucycles();
@@ -82,20 +123,27 @@ int main(int ac, char **av)
 		sum = loop(a, b, len);
 		cpucycles();
 	}
+
 	time_end = cpucycles();
 	/* ---------------------------------- */
-	printf("sum = %d; Avg time delta[Loop + Read] = %llu\n", sum,
-	       (time_end - time_start)/1000);
+	result = (time_end-time_start)/1000;
+	printf("\nsum=%d Avg count [ Loop + Read ] = %ld\n", sum,
+	       (time_end-time_start)/1000);
 	time_start = time_end = 0;
 	/* --------------------Critical section-------------- */
 	time_start = cpucycles();
 	for (i = 0; i < 1000; i++)
 		sum = loop(a, b, len);
+
 	time_end = cpucycles();
 	/* ---------------------------------- */
-	printf("sum = %d; Avg time delta[Loop]\t = %llu\n", sum,
-	       (time_end - time_start)/1000);
+	printf("sum=%d Avg count [ Loop        ] = %ld\n", sum,
+	       (time_end-time_start)/1000);
+	printf("\n--------------------------------------------------------\n");
+	printf("\tDelay[cpucycles]=%d", result-((time_end-time_start)/1000));
+	printf("\n--------------------------------------------------------\n");
 	free(a);
 	free(b);
+	close(fddev);
 	return 0;
 }