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Message-ID: <20241216070244.14450-5-adrian.hunter@intel.com>
Date: Mon, 16 Dec 2024 09:02:40 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>
Cc: Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>,
Leo Yan <leo.yan@....com>,
linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org
Subject: [PATCH V16 4/7] perf tools: Add missing_features for aux_start_paused, aux_pause, aux_resume
Display "feature is not supported" error message if aux_start_paused,
aux_pause or aux_resume result in a perf_event_open() error.
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
Changes in V15:
Re-base on new API probe method of missing feature detection
and add probe for aux_action.
Changes in V13:
Add error message also in EOPNOTSUPP case (Leo)
tools/perf/util/evsel.c | 98 ++++++++++++++++++++++++++++++++++++-----
tools/perf/util/evsel.h | 1 +
2 files changed, 87 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 0a1b797d1f00..f6bf845808d6 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2145,16 +2145,17 @@ int evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus,
return err;
}
-static bool has_attr_feature(struct perf_event_attr *attr, unsigned long flags)
+static bool __has_attr_feature(struct perf_event_attr *attr,
+ struct perf_cpu cpu, unsigned long flags)
{
- int fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, /*cpu=*/-1,
+ int fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, cpu.cpu,
/*group_fd=*/-1, flags);
close(fd);
if (fd < 0) {
attr->exclude_kernel = 1;
- fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, /*cpu=*/-1,
+ fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, cpu.cpu,
/*group_fd=*/-1, flags);
close(fd);
}
@@ -2162,7 +2163,7 @@ static bool has_attr_feature(struct perf_event_attr *attr, unsigned long flags)
if (fd < 0) {
attr->exclude_hv = 1;
- fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, /*cpu=*/-1,
+ fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, cpu.cpu,
/*group_fd=*/-1, flags);
close(fd);
}
@@ -2170,7 +2171,7 @@ static bool has_attr_feature(struct perf_event_attr *attr, unsigned long flags)
if (fd < 0) {
attr->exclude_guest = 1;
- fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, /*cpu=*/-1,
+ fd = syscall(SYS_perf_event_open, attr, /*pid=*/0, cpu.cpu,
/*group_fd=*/-1, flags);
close(fd);
}
@@ -2182,6 +2183,13 @@ static bool has_attr_feature(struct perf_event_attr *attr, unsigned long flags)
return fd >= 0;
}
+static bool has_attr_feature(struct perf_event_attr *attr, unsigned long flags)
+{
+ struct perf_cpu cpu = {.cpu = -1};
+
+ return __has_attr_feature(attr, cpu, flags);
+}
+
static void evsel__detect_missing_pmu_features(struct evsel *evsel)
{
struct perf_event_attr attr = {
@@ -2270,7 +2278,65 @@ static void evsel__detect_missing_brstack_features(struct evsel *evsel)
errno = old_errno;
}
-static bool evsel__detect_missing_features(struct evsel *evsel)
+static bool evsel__probe_aux_action(struct evsel *evsel, struct perf_cpu cpu)
+{
+ struct perf_event_attr attr = evsel->core.attr;
+ int old_errno = errno;
+
+ attr.disabled = 1;
+ attr.aux_start_paused = 1;
+
+ if (__has_attr_feature(&attr, cpu, /*flags=*/0)) {
+ errno = old_errno;
+ return true;
+ }
+
+ /*
+ * EOPNOTSUPP means the kernel supports the feature but the PMU does
+ * not, so keep that distinction if possible.
+ */
+ if (errno != EOPNOTSUPP)
+ errno = old_errno;
+
+ return false;
+}
+
+static void evsel__detect_missing_aux_action_feature(struct evsel *evsel, struct perf_cpu cpu)
+{
+ static bool detection_done;
+ struct evsel *leader;
+
+ /*
+ * Don't bother probing aux_action if it is not being used or has been
+ * probed before.
+ */
+ if (!evsel->core.attr.aux_action || detection_done)
+ return;
+
+ detection_done = true;
+
+ /*
+ * The leader is an AUX area event. If it has failed, assume the feature
+ * is not supported.
+ */
+ leader = evsel__leader(evsel);
+ if (evsel == leader) {
+ perf_missing_features.aux_action = true;
+ return;
+ }
+
+ /*
+ * AUX area event with aux_action must have been opened successfully
+ * already, so feature is supported.
+ */
+ if (leader->core.attr.aux_action)
+ return;
+
+ if (!evsel__probe_aux_action(leader, cpu))
+ perf_missing_features.aux_action = true;
+}
+
+static bool evsel__detect_missing_features(struct evsel *evsel, struct perf_cpu cpu)
{
static bool detection_done = false;
struct perf_event_attr attr = {
@@ -2280,6 +2346,8 @@ static bool evsel__detect_missing_features(struct evsel *evsel)
};
int old_errno;
+ evsel__detect_missing_aux_action_feature(evsel, cpu);
+
evsel__detect_missing_pmu_features(evsel);
if (evsel__has_br_stack(evsel))
@@ -2494,6 +2562,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
int idx, thread, nthreads;
int pid = -1, err, old_errno;
enum rlimit_action set_rlimit = NO_CHANGE;
+ struct perf_cpu cpu;
if (evsel__is_retire_lat(evsel))
return tpebs_start(evsel->evlist);
@@ -2531,6 +2600,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
}
for (idx = start_cpu_map_idx; idx < end_cpu_map_idx; idx++) {
+ cpu = perf_cpu_map__cpu(cpus, idx);
for (thread = 0; thread < nthreads; thread++) {
int fd, group_fd;
@@ -2551,10 +2621,9 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
/* Debug message used by test scripts */
pr_debug2_peo("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx",
- pid, perf_cpu_map__cpu(cpus, idx).cpu, group_fd, evsel->open_flags);
+ pid, cpu.cpu, group_fd, evsel->open_flags);
- fd = sys_perf_event_open(&evsel->core.attr, pid,
- perf_cpu_map__cpu(cpus, idx).cpu,
+ fd = sys_perf_event_open(&evsel->core.attr, pid, cpu.cpu,
group_fd, evsel->open_flags);
FD(evsel, idx, thread) = fd;
@@ -2570,8 +2639,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
bpf_counter__install_pe(evsel, idx, fd);
if (unlikely(test_attr__enabled())) {
- test_attr__open(&evsel->core.attr, pid,
- perf_cpu_map__cpu(cpus, idx),
+ test_attr__open(&evsel->core.attr, pid, cpu,
fd, group_fd, evsel->open_flags);
}
@@ -2626,7 +2694,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
if (err == -EMFILE && rlimit__increase_nofile(&set_rlimit))
goto retry_open;
- if (err == -EINVAL && evsel__detect_missing_features(evsel))
+ if (err == -EINVAL && evsel__detect_missing_features(evsel, cpu))
goto fallback_missing_features;
if (evsel__precise_ip_fallback(evsel))
@@ -3585,6 +3653,10 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
return scnprintf(msg, size,
"%s: PMU Hardware doesn't support 'aux_output' feature",
evsel__name(evsel));
+ if (evsel->core.attr.aux_action)
+ return scnprintf(msg, size,
+ "%s: PMU Hardware doesn't support 'aux_action' feature",
+ evsel__name(evsel));
if (evsel->core.attr.sample_period != 0)
return scnprintf(msg, size,
"%s: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'",
@@ -3615,6 +3687,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
return scnprintf(msg, size, "clockid feature not supported.");
if (perf_missing_features.clockid_wrong)
return scnprintf(msg, size, "wrong clockid (%d).", clockid);
+ if (perf_missing_features.aux_action)
+ return scnprintf(msg, size, "The 'aux_action' feature is not supported, update the kernel.");
if (perf_missing_features.aux_output)
return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
if (!target__has_cpu(target))
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 93b6244ec302..76749bb0e1a5 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -207,6 +207,7 @@ struct perf_missing_features {
bool weight_struct;
bool read_lost;
bool branch_counters;
+ bool aux_action;
bool inherit_sample_read;
};
--
2.43.0
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