perf: Add a perf trace option to check samples ordering reliability
To ensure sample events time reordering is reliable, add a -d option
to perf trace to check that automatically.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 1d034f6..77f556f 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -11,6 +11,8 @@
static char const *script_name;
static char const *generate_script_lang;
+static bool debug_ordering;
+static u64 last_timestamp;
static int default_start_script(const char *script __unused,
int argc __unused,
@@ -87,6 +89,14 @@
}
if (session->sample_type & PERF_SAMPLE_RAW) {
+ if (debug_ordering) {
+ if (data.time < last_timestamp) {
+ pr_err("Samples misordered, previous: %llu "
+ "this: %llu\n", last_timestamp,
+ data.time);
+ }
+ last_timestamp = data.time;
+ }
/*
* FIXME: better resolve from pid from the struct trace_entry
* field, although it should be the same than this perf
@@ -532,6 +542,8 @@
"generate perf-trace.xx script in specified language"),
OPT_STRING('i', "input", &input_name, "file",
"input file name"),
+ OPT_BOOLEAN('d', "debug-ordering", &debug_ordering,
+ "check that samples time ordering is monotonic"),
OPT_END()
};