perf intel-pt: Use itrace debug log flags to suppress some messages

The "d" option may be followed by flags which affect what debug messages
will or will not be logged. Each flag must be preceded by either '+' or
'-'. The flags support by Intel PT are:

		-a	Suppress logging of perf events

Suppressing perf events is useful for decreasing the size of the log.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20200710151104.15137-9-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-intel-pt.txt

@@ -882,7 +882,10 @@ For example, for errors but not overflow or data lost errors:
 
 The "d" option will cause the creation of a file "intel_pt.log" containing all
 decoded packets and instructions.  Note that this option slows down the decoder
-and that the resulting file may be very large.
+and that the resulting file may be very large.  The "d" option may be followed
+by flags which affect what debug messages will or will not be logged. Each flag
+must be preceded by either '+' or '-'. The flags support by Intel PT are:
+		-a	Suppress logging of perf events
 
 In addition, the period of the "instructions" event can be specified. e.g.
 

tools/perf/util/intel-pt.c

@@ -249,6 +249,11 @@ static void intel_pt_dump_sample(struct perf_session *session,
 	intel_pt_dump(pt, sample->aux_sample.data, sample->aux_sample.size);
 }
 
+static bool intel_pt_log_events(struct intel_pt *pt)
+{
+	return !(pt->synth_opts.log_minus_flags & AUXTRACE_LOG_FLG_ALL_PERF_EVTS);
+}
+
 static int intel_pt_do_fix_overlap(struct intel_pt *pt, struct auxtrace_buffer *a,
 				   struct auxtrace_buffer *b)
 {
@@ -2586,10 +2591,6 @@ static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event,
 		return -EINVAL;
 	}
 
-	intel_pt_log("context_switch: cpu %d pid %d tid %d time %"PRIu64" tsc %#"PRIx64"\n",
-		     cpu, pid, tid, sample->time, perf_time_to_tsc(sample->time,
-		     &pt->tc));
-
 	ret = intel_pt_sync_switch(pt, cpu, tid, sample->time);
 	if (ret <= 0)
 		return ret;
@@ -2746,9 +2747,11 @@ static int intel_pt_process_event(struct perf_session *session,
 	if (!err && event->header.type == PERF_RECORD_TEXT_POKE)
 		err = intel_pt_text_poke(pt, event);
 
-	intel_pt_log("event %u: cpu %d time %"PRIu64" tsc %#"PRIx64" ",
-		     event->header.type, sample->cpu, sample->time, timestamp);
-	intel_pt_log_event(event);
+	if (intel_pt_enable_logging && intel_pt_log_events(pt)) {
+		intel_pt_log("event %u: cpu %d time %"PRIu64" tsc %#"PRIx64" ",
+			     event->header.type, sample->cpu, sample->time, timestamp);
+		intel_pt_log_event(event);
+	}
 
 	return err;
 }