linux-kernel - [PATCH V2 01/12] perf auxtrace: Add Z itrace option for timeless decoding

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Message-Id: <20210430070309.17624-2-adrian.hunter@intel.com>
Date:   Fri, 30 Apr 2021 10:02:58 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>, Andi Kleen <ak@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH V2 01/12] 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@...el.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 0f1005209a2b..2d586fe5e4c5 100644
--- a/tools/perf/Documentation/itrace.txt
+++ b/tools/perf/Documentation/itrace.txt
@@ -20,6 +20,7 @@
 		L	synthesize last branch entries on existing event records
 		s       skip initial number of events
 		q	quicker (less detailed) decoding
+		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 5b6ccb90b397..48b88e2bca1e 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1569,6 +1569,9 @@ int itrace_parse_synth_opts(const struct option *opt, const char *str,
 		case 'q':
 			synth_opts->quick += 1;
 			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 a4fbb33b7245..59c3c05384a4 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -89,6 +89,7 @@ enum itrace_period_type {
  * @tlb: whether to synthesize TLB events
  * @remote_access: whether to synthesize remote access events
  * @mem: whether to synthesize memory 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
@@ -128,6 +129,7 @@ struct itrace_synth_opts {
 	bool			tlb;
 	bool			remote_access;
 	bool			mem;
+	bool			timeless_decoding;
 	unsigned int		callchain_sz;
 	unsigned int		last_branch_sz;
 	unsigned long long	period;
-- 
2.25.1