[RFC v2 5/6] cyclictest: Add JSON output feature

[Daniel Wagner <dwagner@suse.de>]

Write the test results as JSON output to a file. This allows to
simplifies any parsing later on.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 src/cyclictest/cyclictest.c | 51 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index c0e7600b4740..d746e822be72 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -11,6 +11,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <inttypes.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -217,6 +218,7 @@ static struct timespec globalt;
 
 static char fifopath[MAX_PATH];
 static char histfile[MAX_PATH];
+static char outfile[MAX_PATH];
 
 static struct thread_param **parameters;
 static struct thread_stat **statistics;
@@ -843,6 +845,7 @@ static void display_help(int error)
 	       "			   latency is hit. Useful for low bandwidth.\n"
 	       "-N       --nsecs           print results in ns instead of us (default us)\n"
 	       "-o RED   --oscope=RED      oscilloscope mode, reduce verbose output by RED\n"
+	       "         --output=FILENAME write final results into FILENAME, JSON formatted\n"
 	       "-p PRIO  --priority=PRIO   priority of highest prio thread\n"
 	       "	 --policy=NAME     policy of measurement thread, where NAME may be one\n"
 	       "                           of: other, normal, batch, idle, fifo or rr.\n"
@@ -950,7 +953,7 @@ enum option_values {
 	OPT_TRIGGER_NODES, OPT_UNBUFFERED, OPT_NUMA, OPT_VERBOSE,
 	OPT_DBGCYCLIC, OPT_POLICY, OPT_HELP, OPT_NUMOPTS,
 	OPT_ALIGNED, OPT_SECALIGNED, OPT_LAPTOP, OPT_SMI,
-	OPT_TRACEMARK, OPT_POSIX_TIMERS,
+	OPT_TRACEMARK, OPT_POSIX_TIMERS, OPT_OUTPUT
 };
 
 /* Process commandline options */
@@ -984,6 +987,7 @@ static void process_options(int argc, char *argv[])
 			{"refresh_on_max",   no_argument,       NULL, OPT_REFRESH },
 			{"nsecs",            no_argument,       NULL, OPT_NSECS },
 			{"oscope",           required_argument, NULL, OPT_OSCOPE },
+			{"output",           required_argument, NULL, OPT_OUTPUT },
 			{"priority",         required_argument, NULL, OPT_PRIORITY },
 			{"quiet",            no_argument,       NULL, OPT_QUIET },
 			{"priospread",       no_argument,       NULL, OPT_PRIOSPREAD },
@@ -1078,6 +1082,9 @@ static void process_options(int argc, char *argv[])
 		case 'o':
 		case OPT_OSCOPE:
 			oscope_reduction = atoi(optarg); break;
+		case OPT_OUTPUT:
+			strncpy(outfile, optarg, strnlen(optarg, MAX_PATH-1));
+			break;
 		case 'p':
 		case OPT_PRIORITY:
 			priority = atoi(optarg);
@@ -1695,6 +1702,40 @@ static void rstat_setup(void)
 	return;
 }
 
+static void write_stats(FILE *f, void *data)
+{
+	struct thread_param **par = parameters;
+	unsigned int i, j, comma;
+	struct thread_stat *s;
+
+	fprintf(f, "  \"num_threads\": %d,\n", num_threads);
+	fprintf(f, "  \"resolution_in_ns\": %u,\n", use_nsecs);
+	fprintf(f, "  \"thread\": {\n");
+	for (i = 0; i < num_threads; i++) {
+		fprintf(f, "    \"%u\": {\n", i);
+
+		fprintf(f, "      \"histogram\": {");
+		s = par[i]->stats;
+		for (j = 0, comma = 0; j < histogram; j++) {
+			if (s->hist_array[j] == 0)
+				continue;
+			fprintf(f, "%s", comma ? ",\n" : "\n");
+			fprintf(f, "        \"%u\": %" PRIu64,j, s->hist_array[j]);
+			comma = 1;
+		}
+		if (comma)
+			fprintf(f, "\n");
+		fprintf(f, "      },\n");
+		fprintf(f, "      \"cycles\": %" PRIu64 ",\n", s->cycles);
+		fprintf(f, "      \"min\": %" PRIu64 ",\n", s->min);
+		fprintf(f, "      \"max\": %" PRIu64 ",\n", s->max);
+		fprintf(f, "      \"avg\": %.2f,\n", s->avg/s->cycles);
+		fprintf(f, "      \"cpu\": %d,\n", par[i]->cpu);
+		fprintf(f, "      \"node\": %d\n", par[i]->node);
+		fprintf(f, "    }%s\n", i == num_threads - 1 ? "" : ",");
+	}
+	fprintf(f, "  }\n");
+}
 
 int main(int argc, char **argv)
 {
@@ -2038,6 +2079,14 @@ int main(int argc, char **argv)
 	if (!verbose && !quiet && refresh_on_max)
 		printf("\033[%dB", num_threads + 2);
 
+	if (strlen(outfile) != 0) {
+		FILE *f = fopen(outfile, "w");
+		if (!f)
+			err_exit(errno, "Failed to open output file '%s'", outfile);
+		rt_write_json(f, argc, argv, write_stats, NULL);
+		fclose(f);
+	}
+
 	if (quiet)
 		quiet = 2;
 	for (i = 0; i < num_threads; i++) {
-- 
2.29.2