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

From: Adrian Hunter
Date: Thu Apr 29 2021 - 08:58:52 EST


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@xxxxxxxxx>
---
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;
--
2.17.1