From be80ff79760eeee079aa9dc8a2eb9ce00de45dda Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@intel.com>
Date: Fri, 30 Apr 2021 10:02:58 +0300
Subject: [PATCH] perf auxtrace: Add Z itrace option for timeless decoding

Issues correlating timestamps can be avoided with timeless decoding. Add
an option for that, so that timeless decoding can be used even when
timestamps are present.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20210430070309.17624-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/itrace.txt | 1 +
 tools/perf/util/auxtrace.c          | 3 +++
 tools/perf/util/auxtrace.h          | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt
index c2182cbabde3..24a345a77c32 100644
--- a/tools/perf/Documentation/itrace.txt
+++ b/tools/perf/Documentation/itrace.txt
@@ -10,6 +10,7 @@
 		g	synthesize a call chain (use with i or x)
 		l	synthesize last branch entries (use with i or x)
 		s       skip initial number of events
+		Z	prefer to ignore timestamps (so-called "timeless" decoding)
 
 	The default is all events i.e. the same as --itrace=ibxwpe,
 	except for perf script where it is --itrace=ce
diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index ec0af36697c4..9fb238706809 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1114,6 +1114,9 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 				goto out_err;
 			p = endptr;
 			break;
+		case 'Z':
+			synth_opts->timeless_decoding = true;
+			break;
 		case ' ':
 		case ',':
 			break;
diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index e9b4c5edf78b..a612ba746318 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -68,6 +68,7 @@ enum itrace_period_type {
  * @callchain: add callchain to 'instructions' events
  * @thread_stack: feed branches to the thread_stack
  * @last_branch: add branch context to 'instruction' events
+ * @timeless_decoding: prefer "timeless" decoding i.e. ignore timestamps
  * @callchain_sz: maximum callchain size
  * @last_branch_sz: branch context size
  * @period: 'instructions' events period
@@ -94,6 +95,7 @@ struct itrace_synth_opts {
 	bool			callchain;
 	bool			thread_stack;
 	bool			last_branch;
+	bool			timeless_decoding;
 	unsigned int		callchain_sz;
 	unsigned int		last_branch_sz;
 	unsigned long long	period;
-- 
2.32.0.605.g8dce9f2422-goog