perf script: Add a setting for maximum stack depth

Add a setting for maximum stack depth in preparation for allowing for
synthesized callchains.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-19-git-send-email-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-script.c

@@ -33,6 +33,8 @@ static bool			nanosecs;
 static const char		*cpu_list;
 static DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);
 
+static unsigned int scripting_max_stack = PERF_MAX_STACK_DEPTH;
+
 enum perf_output_field {
 	PERF_OUTPUT_COMM            = 1U << 0,
 	PERF_OUTPUT_TID             = 1U << 1,
@@ -475,7 +477,7 @@ static void print_sample_bts(union perf_event *event,
 			}
 		}
 		perf_evsel__print_ip(evsel, sample, al, print_opts,
-				     PERF_MAX_STACK_DEPTH);
+				     scripting_max_stack);
 	}
 
 	/* print branch_to information */
@@ -552,7 +554,7 @@ static void process_event(union perf_event *event, struct perf_sample *sample,
 
 		perf_evsel__print_ip(evsel, sample, al,
 				     output[attr->type].print_ip_opts,
-				     PERF_MAX_STACK_DEPTH);
+				     scripting_max_stack);
 	}
 
 	if (PRINT_FIELD(IREGS))

tools/perf/util/session.c

@@ -1800,7 +1800,7 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, struct perf_sample *sample,
 
 		if (thread__resolve_callchain(al->thread, evsel,
 					      sample, NULL, NULL,
-					      PERF_MAX_STACK_DEPTH) != 0) {
+					      stack_depth) != 0) {
 			if (verbose)
 				error("Failed to resolve callchain. Skipping\n");
 			return;