[PATCH 5/7] perf: cs-etm: Allow user to override timestamp and contextid settings

From: James Clark
Date: Mon Apr 24 2023 - 09:49:04 EST


Timestamps and context tracking are automatically enabled in per-core
mode and it's impossible to override this. Use the new utility function
to set them conditionally.

Signed-off-by: James Clark <james.clark@xxxxxxx>
---
tools/perf/arch/arm/util/cs-etm.c | 29 +++++++++++++++++++++++------
tools/perf/arch/arm/util/pmu.c | 2 ++
tools/perf/util/cs-etm.h | 2 ++
3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index af0a2400c655..77cb03e6ff87 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -324,8 +324,6 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
perf_can_record_switch_events())
opts->record_switch_events = true;

- cs_etm_evsel->core.attr.freq = 0;
- cs_etm_evsel->core.attr.sample_period = 1;
cs_etm_evsel->needs_auxtrace_mmap = true;
opts->full_auxtrace = true;

@@ -430,10 +428,10 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
* when a context switch happened.
*/
if (!perf_cpu_map__empty(cpus)) {
- cs_etm_evsel->core.attr.config |=
- perf_pmu__format_bits(&cs_etm_pmu->format, "timestamp");
- cs_etm_evsel->core.attr.config |=
- perf_pmu__format_bits(&cs_etm_pmu->format, "contextid");
+ evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,
+ "timestamp", 1);
+ evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,
+ "contextid", 1);
}

/* Add dummy event to keep tracking */
@@ -914,3 +912,22 @@ struct auxtrace_record *cs_etm_record_init(int *err)
out:
return NULL;
}
+
+/*
+ * Set a default config to enable the user changed config tracking mechanism
+ * (CFG_CHG and evsel__set_config_if_unset()). If no default is set then user
+ * changes aren't tracked.
+ */
+struct perf_event_attr *
+cs_etm_get_default_config(struct perf_pmu *pmu __maybe_unused)
+{
+ struct perf_event_attr *attr;
+
+ attr = zalloc(sizeof(struct perf_event_attr));
+ if (!attr)
+ return NULL;
+
+ attr->sample_period = 1;
+
+ return attr;
+}
diff --git a/tools/perf/arch/arm/util/pmu.c b/tools/perf/arch/arm/util/pmu.c
index 887c8addc491..860a8b42b4b5 100644
--- a/tools/perf/arch/arm/util/pmu.c
+++ b/tools/perf/arch/arm/util/pmu.c
@@ -12,6 +12,7 @@
#include "arm-spe.h"
#include "hisi-ptt.h"
#include "../../../util/pmu.h"
+#include "../cs-etm.h"

struct perf_event_attr
*perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
@@ -20,6 +21,7 @@ struct perf_event_attr
if (!strcmp(pmu->name, CORESIGHT_ETM_PMU_NAME)) {
/* add ETM default config here */
pmu->selectable = true;
+ return cs_etm_get_default_config(pmu);
#if defined(__aarch64__)
} else if (strstarts(pmu->name, ARM_SPE_PMU_NAME)) {
return arm_spe_pmu_default_config(pmu);
diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
index 661f029322e4..16333d35bed4 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -12,6 +12,7 @@
#include <linux/bits.h>

struct perf_session;
+struct perf_pmu;

/*
* Versioning header in case things need to change in the future. That way
@@ -228,6 +229,7 @@ struct cs_etm_packet_queue {

int cs_etm__process_auxtrace_info(union perf_event *event,
struct perf_session *session);
+struct perf_event_attr *cs_etm_get_default_config(struct perf_pmu *pmu);

#ifdef HAVE_CSTRACE_SUPPORT
int cs_etm__get_cpu(u8 trace_chan_id, int *cpu);
--
2.34.1