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>

diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt
index 0f10052..2d586fe 100644 (file)
--- 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 1b4091a..87a9220 100644 (file)
--- 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 a4fbb33..59c3c05 100644 (file)
--- 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;