perf auxtrace: Add itrace 'q' option for quicker, less detailed decoding

The 'q' option is for modes of decoding that are quicker because they
skip or omit decoding some aspects of trace data.

If supported, the 'q' option may be repeated to increase the effect.

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/20200710151104.15137-11-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/itrace.txt

@@ -18,6 +18,7 @@
 		l	synthesize last branch entries (use with i or x)
 		L	synthesize last branch entries on existing event records
 		s       skip initial number of events
+		q	quicker (less detailed) decoding
 
 	The default is all events i.e. the same as --itrace=ibxwpe,
 	except for perf script where it is --itrace=ce
@@ -58,3 +59,5 @@
 	debug messages will or will not be logged. Each flag must be preceded
 	by either '+' or '-'. The flags are:
 		a	all perf events
+
+	If supported, the 'q' option may be repeated to increase the effect.

tools/perf/util/auxtrace.c

@@ -1554,6 +1554,9 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 		case 'a':
 			synth_opts->remote_access = true;
 			break;
+		case 'q':
+			synth_opts->quick += 1;
+			break;
 		case ' ':
 		case ',':
 			break;

tools/perf/util/auxtrace.h

@@ -100,6 +100,7 @@ enum itrace_period_type {
  * @error_minus_flags: flags to affect what errors are reported
  * @log_plus_flags: flags to affect what is logged
  * @log_minus_flags: flags to affect what is logged
+ * @quick: quicker (less detailed) decoding
  */
 struct itrace_synth_opts {
 	bool			set;
@@ -137,6 +138,7 @@ struct itrace_synth_opts {
 	unsigned int		error_minus_flags;
 	unsigned int		log_plus_flags;
 	unsigned int		log_minus_flags;
+	unsigned int		quick;
 };
 
 /**
@@ -642,6 +644,7 @@ bool auxtrace__evsel_is_auxtrace(struct perf_session *session,
 "				l[len]:     		synthesize last branch entries (use with i or x)\n" \
 "				L[len]:			synthesize last branch entries on existing event records\n" \
 "				sNUMBER:    		skip initial number of events\n"		\
+"				q:			quicker (less detailed) decoding\n" \
 "				PERIOD[ns|us|ms|i|t]:   specify period to sample stream\n" \
 "				concatenate multiple options. Default is ibxwpe or cewp\n"