[PATCH v1 1/3] perf evsel: Give warning for broken Intel topdown event grouping

[Ian Rogers <irogers@google.com>]

Extend arch_evsel__open_strerror from just AMD IBS events to Intel
core PMU events, to give a message when a slots event isn't a group
leader or when a perf metric event is duplicated within an event
group. As generating the warning happens after non-arch specific
warnings are generated, disable the missing system wide (-a) flag
warning for the core PMU. This assumes core PMU events should support
per-thread/process and system-wide.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/arch/x86/util/evsel.c | 62 +++++++++++++++++++++++++++++---
 tools/perf/util/evsel.c          |  7 ++--
 tools/perf/util/evsel.h          |  2 +-
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/tools/perf/arch/x86/util/evsel.c b/tools/perf/arch/x86/util/evsel.c
index 9bc80fff3aa0..e67701d26f24 100644
--- a/tools/perf/arch/x86/util/evsel.c
+++ b/tools/perf/arch/x86/util/evsel.c
@@ -1,10 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include "util/evlist.h"
 #include "util/evsel.h"
 #include "util/env.h"
 #include "util/pmu.h"
 #include "util/pmus.h"
+#include "util/stat.h"
+#include "util/strbuf.h"
 #include "linux/string.h"
 #include "topdown.h"
 #include "evsel.h"
@@ -102,13 +106,15 @@ void arch__post_evsel_config(struct evsel *evsel, struct perf_event_attr *attr)
 	}
 }
 
-int arch_evsel__open_strerror(struct evsel *evsel, char *msg, size_t size)
+static int amd_evsel__open_strerror(struct evsel *evsel, char *msg, size_t size)
 {
-	if (!x86__is_amd_cpu())
+	struct perf_pmu *pmu;
+
+	if (evsel->core.attr.precise_ip == 0)
 		return 0;
 
-	if (!evsel->core.attr.precise_ip &&
-	    !(evsel->pmu && !strncmp(evsel->pmu->name, "ibs", 3)))
+	pmu = evsel__find_pmu(evsel);
+	if (!pmu || strncmp(pmu->name, "ibs", 3))
 		return 0;
 
 	/* More verbose IBS errors. */
@@ -118,6 +124,54 @@ int arch_evsel__open_strerror(struct evsel *evsel, char *msg, size_t size)
 		return scnprintf(msg, size, "AMD IBS doesn't support privilege filtering. Try "
 				 "again without the privilege modifiers (like 'k') at the end.");
 	}
+	return 0;
+}
+
+static int intel_evsel__open_strerror(struct evsel *evsel, int err, char *msg, size_t size)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
+	if (err != EINVAL)
+		return 0;
 
+	if (!topdown_sys_has_perf_metrics())
+		return 0;
+
+	if (arch_is_topdown_slots(evsel)) {
+		if (!evsel__is_group_leader(evsel)) {
+			evlist__uniquify_evsel_names(evsel->evlist, &stat_config);
+			evlist__format_evsels(evsel->evlist, &sb, 2048);
+			ret = scnprintf(msg, size, "Topdown slots event can only be group leader "
+					"in '%s'.", sb.buf);
+			strbuf_release(&sb);
+			return ret;
+		}
+	} else if (arch_is_topdown_metrics(evsel)) {
+		struct evsel *pos;
+
+		evlist__for_each_entry(evsel->evlist, pos) {
+			if (pos == evsel || !arch_is_topdown_metrics(pos))
+				continue;
+
+			if (pos->core.attr.config != evsel->core.attr.config)
+				continue;
+
+			evlist__uniquify_evsel_names(evsel->evlist, &stat_config);
+			evlist__format_evsels(evsel->evlist, &sb, 2048);
+			ret = scnprintf(msg, size, "Perf metric event '%s' is duplicated "
+					"in the same group (only one event is allowed) in '%s'.",
+					evsel__name(evsel), sb.buf);
+			strbuf_release(&sb);
+			return ret;
+		}
+	}
 	return 0;
 }
+
+int arch_evsel__open_strerror(struct evsel *evsel, int err, char *msg, size_t size)
+{
+	return x86__is_amd_cpu()
+		? amd_evsel__open_strerror(evsel, msg, size)
+		: intel_evsel__open_strerror(evsel, err, msg, size);
+}
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index d264c143b592..796f3bf35f47 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3716,6 +3716,7 @@ static int dump_perf_event_processes(char *msg, size_t size)
 }
 
 int __weak arch_evsel__open_strerror(struct evsel *evsel __maybe_unused,
+				     int err __maybe_unused,
 				     char *msg __maybe_unused,
 				     size_t size __maybe_unused)
 {
@@ -3725,6 +3726,7 @@ int __weak arch_evsel__open_strerror(struct evsel *evsel __maybe_unused,
 int evsel__open_strerror(struct evsel *evsel, struct target *target,
 			 int err, char *msg, size_t size)
 {
+	struct perf_pmu *pmu;
 	char sbuf[STRERR_BUFSIZE];
 	int printed = 0, enforced = 0;
 	int ret;
@@ -3840,7 +3842,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 			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))
+		pmu = evsel__find_pmu(evsel);
+		if (!pmu->is_core && !target__has_cpu(target))
 			return scnprintf(msg, size,
 	"Invalid event (%s) in per-thread mode, enable system wide with '-a'.",
 					evsel__name(evsel));
@@ -3853,7 +3856,7 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 		break;
 	}
 
-	ret = arch_evsel__open_strerror(evsel, msg, size);
+	ret = arch_evsel__open_strerror(evsel, err, msg, size);
 	if (ret)
 		return ret;
 
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 5797a02e5d6a..e927a3a4fe0e 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -341,7 +341,7 @@ void evsel__set_sample_id(struct evsel *evsel, bool use_sample_identifier);
 
 void arch_evsel__set_sample_weight(struct evsel *evsel);
 void arch__post_evsel_config(struct evsel *evsel, struct perf_event_attr *attr);
-int arch_evsel__open_strerror(struct evsel *evsel, char *msg, size_t size);
+int arch_evsel__open_strerror(struct evsel *evsel, int err, char *msg, size_t size);
 
 int evsel__set_filter(struct evsel *evsel, const char *filter);
 int evsel__append_tp_filter(struct evsel *evsel, const char *filter);
-- 
2.51.0.261.g7ce5a0a67e-goog