iio_{readdev,writedev}: Add benchmark feature

Add a new --benchmark (or -B) option.

With this option enabled, no data is written to the standard output (for
iio_readdev) or read from the standard input (for iio_writedev).
Instead, the buffers are flipped as fast as possible. This functionality
permits to benchmark the speed at which the data flows, and compare the
performance of the various backends and/or with various buffer sizes.

Signed-off-by: Paul Cercueil <[email protected]>

Author: pcercuei

tests/iio_common.c

@@ -25,6 +25,7 @@
 #include <inttypes.h>
 #include <getopt.h>
 #include <string.h>
+#include <time.h>
 
 #include "iio_common.h"
 #include "gen_code.h"
@@ -431,3 +432,15 @@ void usage(char *name, const struct option *options,
 	exit(0);
 }
 
+uint64_t get_time_us(void)
+{
+	struct timespec tp;
+
+#ifdef _WIN32
+	timespec_get(&tp, TIME_UTC);
+#else
+	clock_gettime(CLOCK_REALTIME, &tp);
+#endif
+
+	return tp.tv_sec * 1000000ull + tp.tv_nsec / 1000;
+}

tests/iio_common.h

@@ -23,6 +23,7 @@
 #define IIO_TESTS_COMMON_H
 
 #include <getopt.h>
+#include <stdint.h>
 
 /*
  * internal buffers need to be big enough for attributes
@@ -62,6 +63,8 @@ void usage(char *name, const struct option *options, const char *options_descrip
 char ** dup_argv(char * name, int argc, char * argv[]);
 void free_argw(int argc, char * argw[]);
 
+uint64_t get_time_us(void);
+
 /* https://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html
  * {NAME_MAX} : Maximum number of bytes in a filename
  * {PATH_MAX} : Maximum number of bytes in a pathname

tests/iio_readdev.c

@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <getopt.h>
 #include <iio.h>
+#include <inttypes.h>
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
@@ -33,12 +34,14 @@
 
 #define SAMPLES_PER_READ 256
 #define DEFAULT_FREQ_HZ  100
+#define REFILL_PER_BENCHMARK 10
 
 static const struct option options[] = {
 	  {"trigger", required_argument, 0, 't'},
 	  {"buffer-size", required_argument, 0, 'b'},
 	  {"samples", required_argument, 0, 's' },
 	  {"auto", no_argument, 0, 'a'},
+	  {"benchmark", no_argument, 0, 'B'},
 	  {0, 0, 0, 0},
 };
 
@@ -49,6 +52,8 @@ static const char *options_descriptions[] = {
 	"Size of the capture buffer. Default is 256.",
 	"Number of samples to capture, 0 = infinite. Default is 0.",
 	"Scan for available contexts and if only one is available use it.",
+	"Benchmark throughput."
+		"\n\t\t\tStatistics will be printed on the standard input.",
 };
 
 static struct iio_context *ctx;
@@ -186,7 +191,7 @@ static ssize_t print_sample(const struct iio_channel *chn,
 	return (ssize_t) len;
 }
 
-#define MY_OPTS "t:b:s:T:"
+#define MY_OPTS "t:b:s:T:B"
 int main(int argc, char **argv)
 {
 	char **argw;
@@ -198,6 +203,8 @@ int main(int argc, char **argv)
 	ssize_t sample_size;
 	ssize_t ret;
 	struct option *opts;
+	bool mib, benchmark = false;
+	uint64_t before, after, rate, total;
 
 	argw = dup_argv(MY_NAME, argc, argv);
 
@@ -238,6 +245,9 @@ int main(int argc, char **argv)
 			}
 			buffer_size = sanitize_clamp("buffer size", optarg, 1, SIZE_MAX);
 			break;
+		case 'B':
+			benchmark = true;
+			break;
 		case 's':
 			if (!optarg) {
 				fprintf(stderr, "Number of Samples requires an argument\n");
@@ -371,7 +381,11 @@ int main(int argc, char **argv)
 	_setmode(_fileno(stdout), _O_BINARY);
 #endif
 
-	while (app_running) {
+
+	for (i = 0, total = 0; app_running; ) {
+		if (benchmark)
+			before = get_time_us();
+
 		ret = iio_buffer_refill(buffer);
 		if (ret < 0) {
 			if (app_running) {
@@ -382,6 +396,26 @@ int main(int argc, char **argv)
 			break;
 		}
 
+		if (benchmark) {
+			after = get_time_us();
+			rate = buffer_size * sample_size * 1000000ull / (after - before);
+
+			total += rate;
+
+			if (++i == REFILL_PER_BENCHMARK) {
+				mib = rate > 1000000;
+
+				fprintf(stderr, "\33[2K\rThroughput: %" PRIu64 " %ciB/s",
+				       total / (REFILL_PER_BENCHMARK * 1000 * (mib ? 1000 : 1)),
+				       mib ? 'M' : 'K');
+
+				i = 0;
+				total = 0;
+			}
+
+			continue;
+		}
+
 		/* If there are only the samples we requested, we don't need to
 		 * demux */
 		if (iio_buffer_step(buffer) == sample_size) {

tests/iio_writedev.c

@@ -23,6 +23,7 @@
 #include <errno.h>
 #include <getopt.h>
 #include <iio.h>
+#include <inttypes.h>
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
@@ -42,13 +43,15 @@
 
 #define SAMPLES_PER_READ 256
 #define DEFAULT_FREQ_HZ  100
+#define REFILL_PER_BENCHMARK 10
 
 static const struct option options[] = {
 	  {"trigger", required_argument, 0, 't'},
 	  {"buffer-size", required_argument, 0, 'b'},
 	  {"samples", required_argument, 0, 's' },
 	  {"auto", no_argument, 0, 'a'},
 	  {"cyclic", no_argument, 0, 'c'},
+	  {"benchmark", no_argument, 0, 'B'},
 	  {0, 0, 0, 0},
 };
 
@@ -61,6 +64,8 @@ static const char *options_descriptions[] = {
 	"Number of samples to write, 0 = infinite. Default is 0.",
 	"Scan for available contexts and if only one is available use it.",
 	"Use cyclic buffer mode.",
+	"Benchmark throughput."
+		"\n\t\t\tStatistics will be printed on the standard input.",
 };
 
 static struct iio_context *ctx;
@@ -196,7 +201,7 @@ static ssize_t read_sample(const struct iio_channel *chn,
 	return (ssize_t) nb;
 }
 
-#define MY_OPTS "t:b:s:T:ac"
+#define MY_OPTS "t:b:s:T:acB"
 
 int main(int argc, char **argv)
 {
@@ -207,9 +212,10 @@ int main(int argc, char **argv)
 	int c;
 	struct iio_device *dev;
 	ssize_t sample_size;
-	bool cyclic_buffer = false;
+	bool mib, cyclic_buffer = false, benchmark = false;
 	ssize_t ret;
 	struct option *opts;
+	uint64_t before, after, rate, total;
 
 	argw = dup_argv(MY_NAME, argc, argv);
 
@@ -249,6 +255,9 @@ int main(int argc, char **argv)
 			}
 			buffer_size = sanitize_clamp("buffer size", optarg, 1, SIZE_MAX);
 			break;
+		case 'B':
+			benchmark = true;
+			break;
 		case 's':
 			if (!optarg) {
 				fprintf(stderr, "Number of samples requires argument\n");
@@ -275,6 +284,12 @@ int main(int argc, char **argv)
 	if (!ctx)
 		return EXIT_FAILURE;
 
+	if (benchmark && cyclic_buffer) {
+		fprintf(stderr, "Cannot benchmark in cyclic mode.\n");
+		iio_context_destroy(ctx);
+		return EXIT_FAILURE;
+	}
+
 	setup_sig_handler();
 
 	dev = iio_context_find_device(ctx, argw[optind]);
@@ -381,10 +396,12 @@ int main(int argc, char **argv)
 	_setmode(_fileno( stdin ), _O_BINARY);
 #endif
 
-	while (app_running) {
-		/* If there are only the samples we requested, we don't need to
-		 * demux */
-		if (iio_buffer_step(buffer) == sample_size) {
+	for (i = 0, total = 0; app_running; ) {
+		if (benchmark) {
+			before = get_time_us();
+		} else if (iio_buffer_step(buffer) == sample_size) {
+			/* If there are only the samples we requested, we don't
+			 * need to demux */
 			void *start = iio_buffer_start(buffer);
 			size_t write_len, len = (intptr_t) iio_buffer_end(buffer)
 				- (intptr_t) start;
@@ -424,6 +441,25 @@ int main(int argc, char **argv)
 			break;
 		}
 
+		if (benchmark) {
+			after = get_time_us();
+			rate = buffer_size * sample_size * 1000000ull / (after - before);
+
+			total += rate;
+
+			if (++i == REFILL_PER_BENCHMARK) {
+				mib = rate > 1000000;
+
+				fprintf(stderr, "\33[2K\rThroughput: %" PRIu64 " %ciB/s",
+				       total / (REFILL_PER_BENCHMARK * 1000 * (mib ? 1000 : 1)),
+				       mib ? 'M' : 'K');
+
+				i = 0;
+				total = 0;
+			}
+		}
+
+
 		while(cyclic_buffer && app_running) {
 #ifdef _WIN32
 			Sleep(1000);