perf auxtrace: Fix period type 'i' not working

PERF_ITRACE_PERIOD_INSTRUCTIONS is zero so it got overwritten by the
default period type.

Fix by checking if the period type was set rather than if the value was
zero when applying the default.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-12-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/auxtrace.c

@@ -942,6 +942,7 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 	struct itrace_synth_opts *synth_opts = opt->value;
 	const char *p;
 	char *endptr;
+	bool period_type_set = false;
 
 	synth_opts->set = true;
 
@@ -970,10 +971,12 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 				case 'i':
 					synth_opts->period_type =
 						PERF_ITRACE_PERIOD_INSTRUCTIONS;
+					period_type_set = true;
 					break;
 				case 't':
 					synth_opts->period_type =
 						PERF_ITRACE_PERIOD_TICKS;
+					period_type_set = true;
 					break;
 				case 'm':
 					synth_opts->period *= 1000;
@@ -986,6 +989,7 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 						goto out_err;
 					synth_opts->period_type =
 						PERF_ITRACE_PERIOD_NANOSECS;
+					period_type_set = true;
 					break;
 				case '\0':
 					goto out;
@@ -1039,7 +1043,7 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 	}
 out:
 	if (synth_opts->instructions) {
-		if (!synth_opts->period_type)
+		if (!period_type_set)
 			synth_opts->period_type =
 					PERF_ITRACE_DEFAULT_PERIOD_TYPE;
 		if (!synth_opts->period)