[PATCH 4/5] perf tools: Add evlist__add_sched_switch()

From: Namhyung Kim
Date: Mon Oct 03 2022 - 16:47:17 EST


Add a help to create a system-wide sched_switch event. One merit is
that it sets the system-wide bit before adding it to evlist so that
the libperf can handle the cpu and thread maps correctly.

Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/arch/x86/util/intel-pt.c | 15 +++++----------
tools/perf/tests/switch-tracking.c | 15 +++++----------
tools/perf/util/evlist.c | 17 +++++++++++++++++
tools/perf/util/evlist.h | 1 +
4 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
index 13933020a79e..793b35f2221a 100644
--- a/tools/perf/arch/x86/util/intel-pt.c
+++ b/tools/perf/arch/x86/util/intel-pt.c
@@ -11,6 +11,7 @@
#include <linux/bitops.h>
#include <linux/log2.h>
#include <linux/zalloc.h>
+#include <linux/err.h>
#include <cpuid.h>

#include "../../../util/session.h"
@@ -426,20 +427,14 @@ static int intel_pt_track_switches(struct evlist *evlist)
if (!evlist__can_select_event(evlist, sched_switch))
return -EPERM;

- err = parse_event(evlist, sched_switch);
- if (err) {
- pr_debug2("%s: failed to parse %s, error %d\n",
+ evsel = evlist__add_sched_switch(evlist, true);
+ if (IS_ERR(evsel)) {
+ err = PTR_ERR(evsel);
+ pr_debug2("%s: failed to create %s, error = %d\n",
__func__, sched_switch, err);
return err;
}

- evsel = evlist__last(evlist);
-
- evsel__set_sample_bit(evsel, CPU);
- evsel__set_sample_bit(evsel, TIME);
-
- evsel->core.system_wide = true;
- evsel->no_aux_samples = true;
evsel->immediate = true;

return 0;
diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
index 2d46af9ef935..87f565c7f650 100644
--- a/tools/perf/tests/switch-tracking.c
+++ b/tools/perf/tests/switch-tracking.c
@@ -6,6 +6,7 @@
#include <time.h>
#include <stdlib.h>
#include <linux/zalloc.h>
+#include <linux/err.h>
#include <perf/cpumap.h>
#include <perf/evlist.h>
#include <perf/mmap.h>
@@ -398,19 +399,13 @@ static int test__switch_tracking(struct test_suite *test __maybe_unused, int sub
goto out;
}

- err = parse_event(evlist, sched_switch);
- if (err) {
- pr_debug("Failed to parse event %s\n", sched_switch);
+ switch_evsel = evlist__add_sched_switch(evlist, true);
+ if (IS_ERR(switch_evsel)) {
+ err = PTR_ERR(switch_evsel);
+ pr_debug("Failed to create event %s\n", sched_switch);
goto out_err;
}

- switch_evsel = evlist__last(evlist);
-
- evsel__set_sample_bit(switch_evsel, CPU);
- evsel__set_sample_bit(switch_evsel, TIME);
-
- switch_evsel->core.system_wide = true;
- switch_evsel->no_aux_samples = true;
switch_evsel->immediate = true;

/* Test moving an event to the front */
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index dcf57b271ff1..6612b00949e7 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -288,6 +288,23 @@ struct evsel *evlist__add_aux_dummy(struct evlist *evlist, bool system_wide)
return evsel;
}

+struct evsel *evlist__add_sched_switch(struct evlist *evlist, bool system_wide)
+{
+ struct evsel *evsel = evsel__newtp_idx("sched", "sched_switch", 0);
+
+ if (IS_ERR(evsel))
+ return evsel;
+
+ evsel__set_sample_bit(evsel, CPU);
+ evsel__set_sample_bit(evsel, TIME);
+
+ evsel->core.system_wide = system_wide;
+ evsel->no_aux_samples = true;
+
+ evlist__add(evlist, evsel);
+ return evsel;
+};
+
int evlist__add_attrs(struct evlist *evlist, struct perf_event_attr *attrs, size_t nr_attrs)
{
struct evsel *evsel, *n;
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 9d967fe3953a..16734c6756b3 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -127,6 +127,7 @@ static inline struct evsel *evlist__add_dummy_on_all_cpus(struct evlist *evlist)
{
return evlist__add_aux_dummy(evlist, true);
}
+struct evsel *evlist__add_sched_switch(struct evlist *evlist, bool system_wide);

int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
evsel__sb_cb_t cb, void *data);
--
2.38.0.rc1.362.ged0d419d3c-goog