linux-kernel - [PATCH 28/49] perf pmu: Save detected hybrid pmus to a global pmu list

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Date:   Mon,  8 Feb 2021 07:25:25 -0800
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, acme@...nel.org, mingo@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, bp@...en8.de, namhyung@...nel.org,
        jolsa@...hat.com, ak@...ux.intel.com, yao.jin@...ux.intel.com,
        alexander.shishkin@...ux.intel.com, adrian.hunter@...el.com
Subject: [PATCH 28/49] perf pmu: Save detected hybrid pmus to a global pmu list

From: Jin Yao <yao.jin@...ux.intel.com>

We identify the cpu_core pmu and cpu_atom pmu by explicitly
checking following files:

For cpu_core, check:
"/sys/bus/event_source/devices/cpu_core/cpus"

For cpu_atom, check:
"/sys/bus/event_source/devices/cpu_atom/cpus"

If the 'cpus' file exists, the pmu exists.

But in order not to hardcode the "cpu_core" and "cpu_atom",
and make the code generic, if the path
"/sys/bus/event_source/devices/cpu_xxx/cpus" exists, the hybrid
pmu exists. All the detected hybrid pmus are linked to a
global list 'perf_pmu__hybrid_pmus' and then next we just need
to iterate the list by using perf_pmu__for_each_hybrid_pmus.

Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
---
 tools/perf/util/pmu.c | 21 +++++++++++++++++++++
 tools/perf/util/pmu.h |  7 +++++++
 2 files changed, 28 insertions(+)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 0c25457..e97b121 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -27,6 +27,7 @@
 #include "fncache.h"
 
 struct perf_pmu perf_pmu__fake;
+LIST_HEAD(perf_pmu__hybrid_pmus);
 
 struct perf_pmu_format {
 	char *name;
@@ -633,11 +634,27 @@ static struct perf_cpu_map *pmu_cpumask(const char *name)
 	return NULL;
 }
 
+static bool pmu_is_hybrid(const char *name)
+{
+	char path[PATH_MAX];
+	const char *sysfs;
+
+	if (strncmp(name, "cpu_", 4))
+		return false;
+
+	sysfs = sysfs__mountpoint();
+	snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, name);
+	return file_available(path);
+}
+
 static bool pmu_is_uncore(const char *name)
 {
 	char path[PATH_MAX];
 	const char *sysfs;
 
+	if (pmu_is_hybrid(name))
+		return false;
+
 	sysfs = sysfs__mountpoint();
 	snprintf(path, PATH_MAX, CPUS_TEMPLATE_UNCORE, sysfs, name);
 	return file_available(path);
@@ -951,6 +968,7 @@ static struct perf_pmu *pmu_lookup(const char *name)
 	pmu->is_uncore = pmu_is_uncore(name);
 	if (pmu->is_uncore)
 		pmu->id = pmu_id(name);
+	pmu->is_hybrid = pmu_is_hybrid(name);
 	pmu->max_precise = pmu_max_precise(name);
 	pmu_add_cpu_aliases(&aliases, pmu);
 	pmu_add_sys_aliases(&aliases, pmu);
@@ -962,6 +980,9 @@ static struct perf_pmu *pmu_lookup(const char *name)
 	list_splice(&aliases, &pmu->aliases);
 	list_add_tail(&pmu->list, &pmus);
 
+	if (pmu->is_hybrid)
+		list_add_tail(&pmu->hybrid_list, &perf_pmu__hybrid_pmus);
+
 	pmu->default_config = perf_pmu__get_default_config(pmu);
 
 	return pmu;
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 0e724d5..99bdb5d 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -5,6 +5,7 @@
 #include <linux/bitmap.h>
 #include <linux/compiler.h>
 #include <linux/perf_event.h>
+#include <linux/list.h>
 #include <stdbool.h>
 #include "parse-events.h"
 #include "pmu-events/pmu-events.h"
@@ -34,6 +35,7 @@ struct perf_pmu {
 	__u32 type;
 	bool selectable;
 	bool is_uncore;
+	bool is_hybrid;
 	bool auxtrace;
 	int max_precise;
 	struct perf_event_attr *default_config;
@@ -42,9 +44,11 @@ struct perf_pmu {
 	struct list_head aliases; /* HEAD struct perf_pmu_alias -> list */
 	struct list_head caps;    /* HEAD struct perf_pmu_caps -> list */
 	struct list_head list;    /* ELEM */
+	struct list_head hybrid_list;
 };
 
 extern struct perf_pmu perf_pmu__fake;
+extern struct list_head perf_pmu__hybrid_pmus;
 
 struct perf_pmu_info {
 	const char *unit;
@@ -124,4 +128,7 @@ int perf_pmu__convert_scale(const char *scale, char **end, double *sval);
 
 int perf_pmu__caps_parse(struct perf_pmu *pmu);
 
+#define perf_pmu__for_each_hybrid_pmus(pmu)	\
+	list_for_each_entry(pmu, &perf_pmu__hybrid_pmus, hybrid_list)
+
 #endif /* __PMU_H */
-- 
2.7.4