[PATCH v4 05/25] perf pmu: Save detected hybrid pmus to a global pmu list

Jin Yao
2021-04-16T14:06:33Z

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

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

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

If the 'cpus' file exists and it has data, the pmu exists.

But in order not to hardcode the "cpu_core" and "cpu_atom",
and make the code in a generic way. So 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 to get all hybrid pmu by using
perf_pmu__for_each_hybrid_pmu.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
v4:
- Check if 'cpus' file is empty. If so, don't create pmu.

v3:
- No functional change.

tools/perf/util/Build | 1 +
tools/perf/util/pmu-hybrid.c | 49 ++++++++++++++++++++++++++++++++++++
tools/perf/util/pmu-hybrid.h | 18 +++++++++++++
tools/perf/util/pmu.c | 9 ++++++-
tools/perf/util/pmu.h | 4 +++
5 files changed, 80 insertions(+), 1 deletion(-)
create mode 100644 tools/perf/util/pmu-hybrid.c
create mode 100644 tools/perf/util/pmu-hybrid.h

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index e3e12f9d4733..37a8a63c7195 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -69,6 +69,7 @@ perf-y += parse-events-bison.o
perf-y += pmu.o
perf-y += pmu-flex.o
perf-y += pmu-bison.o
+perf-y += pmu-hybrid.o
perf-y += trace-event-read.o
perf-y += trace-event-info.o
perf-y += trace-event-scripting.o
diff --git a/tools/perf/util/pmu-hybrid.c b/tools/perf/util/pmu-hybrid.c
new file mode 100644
index 000000000000..8ed0e6e1776d
--- /dev/null
+++ b/tools/perf/util/pmu-hybrid.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/list.h>
+#include <linux/compiler.h>
+#include <linux/string.h>
+#include <linux/zalloc.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <locale.h>
+#include <api/fs/fs.h>
+#include "fncache.h"
+#include "pmu-hybrid.h"
+
+LIST_HEAD(perf_pmu__hybrid_pmus);
+
+bool perf_pmu__hybrid_mounted(const char *name)
+{
+ char path[PATH_MAX];
+ const char *sysfs;
+ FILE *file;
+ int n, cpu;
+
+ if (strncmp(name, "cpu_", 4))
+ return false;
+
+ sysfs = sysfs__mountpoint();
+ if (!sysfs)
+ return false;
+
+ snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, name);
+ if (!file_available(path))
+ return false;
+
+ file = fopen(path, "r");
+ if (!file)
+ return false;
+
+ n = fscanf(file, "%u", &cpu);
+ fclose(file);
+ if (n <= 0)
+ return false;
+
+ return true;
+}
diff --git a/tools/perf/util/pmu-hybrid.h b/tools/perf/util/pmu-hybrid.h
new file mode 100644
index 000000000000..35bed3714438
--- /dev/null
+++ b/tools/perf/util/pmu-hybrid.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PMU_HYBRID_H
+#define __PMU_HYBRID_H
+
+#include <linux/perf_event.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <stdbool.h>
+#include "pmu.h"
+
+extern struct list_head perf_pmu__hybrid_pmus;
+
+#define perf_pmu__for_each_hybrid_pmu(pmu) \
+ list_for_each_entry(pmu, &perf_pmu__hybrid_pmus, hybrid_list)
+
+bool perf_pmu__hybrid_mounted(const char *name);
+
+#endif /* __PMU_HYBRID_H */
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 44225838eb03..6e49c7b8ad71 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -25,6 +25,7 @@
#include "string2.h"
#include "strbuf.h"
#include "fncache.h"
+#include "pmu-hybrid.h"

struct perf_pmu perf_pmu__fake;

@@ -613,7 +614,6 @@ static struct perf_cpu_map *__pmu_cpumask(const char *path)
*/
#define SYS_TEMPLATE_ID "./bus/event_source/devices/%s/identifier"
#define CPUS_TEMPLATE_UNCORE "%s/bus/event_source/devices/%s/cpumask"
-#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"

static struct perf_cpu_map *pmu_cpumask(const char *name)
{
@@ -645,6 +645,9 @@ static bool pmu_is_uncore(const char *name)
char path[PATH_MAX];
const char *sysfs;

+ if (perf_pmu__hybrid_mounted(name))
+ return false;
+
sysfs = sysfs__mountpoint();
snprintf(path, PATH_MAX, CPUS_TEMPLATE_UNCORE, sysfs, name);
return file_available(path);
@@ -951,6 +954,7 @@ 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 = perf_pmu__hybrid_mounted(name);
pmu->max_precise = pmu_max_precise(name);
pmu_add_cpu_aliases(&aliases, pmu);
pmu_add_sys_aliases(&aliases, pmu);
@@ -962,6 +966,9 @@ 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 4f100768c264..9a2f89eeab6f 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"
@@ -19,6 +20,7 @@ enum {

#define PERF_PMU_FORMAT_BITS 64
#define EVENT_SOURCE_DEVICE_PATH "/bus/event_source/devices/"
+#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"

struct perf_event_attr;

@@ -34,6 +36,7 @@ struct perf_pmu {
__u32 type;
bool selectable;
bool is_uncore;
+ bool is_hybrid;
bool auxtrace;
int max_precise;
struct perf_event_attr *default_config;
@@ -42,6 +45,7 @@ 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;
--
2.17.1