[PATCH v3 0/2] perf tools: Add PMU alias support

[PATCH v3 0/2] perf tools: Add PMU alias support

[Jin Yao]

A perf uncore PMU may have two PMU names, a real name and an alias name.
With this patch set, the perf tool can monitor the PMU with either the
real name or the alias.

Use the real name,
 $ perf stat -e uncore_cha_2/event=1/ -x,
   4044879584,,uncore_cha_2/event=1/,2528059205,100.00,,

Use the alias,
 $ perf stat -e uncore_type_0_2/event=1/ -x,
   3659675336,,uncore_type_0_2/event=1/,2287306455,100.00,,

v3:
---
1. Use fgets() to replace fscanf().
2. Resource cleanup.

v2:
---
Add test case to verify the real name and alias name having same effect.

Jin Yao (1):
  perf tests: Test for PMU alias

Kan Liang (1):
  perf pmu: Add PMU alias support

 tools/perf/arch/x86/util/pmu.c  | 129 +++++++++++++++++++++++++++++++-
 tools/perf/tests/parse-events.c |  92 +++++++++++++++++++++++
 tools/perf/util/parse-events.y  |   3 +-
 tools/perf/util/pmu.c           |  26 ++++++-
 tools/perf/util/pmu.h           |   5 ++
 5 files changed, 250 insertions(+), 5 deletions(-)

-- 
2.27.0

[PATCH v3 1/2] perf pmu: Add PMU alias support

[Jin Yao]

From: Kan Liang <kan.liang@linux.intel.com>

A perf uncore PMU may have two PMU names, a real name and an alias. The
alias is exported at /sys/bus/event_source/devices/uncore_*/alias.
The perf tool should support the alias as well.

Add alias_name in the struct perf_pmu to store the alias. For the PMU
which doesn't have an alias. It's NULL.

Introduce two X86 specific functions to retrieve the real name and the
alias separately.

Only go through the sysfs to retrieve the mapping between the real name
and the alias once. The result is cached in a list, uncore_pmu_list.

Nothing changed for the other ARCHs.

With the patch, the perf tool can monitor the PMU with either the real
name or the alias.

Use the real name,
 $ perf stat -e uncore_cha_2/event=1/ -x,
   4044879584,,uncore_cha_2/event=1/,2528059205,100.00,,

Use the alias,
 $ perf stat -e uncore_type_0_2/event=1/ -x,
   3659675336,,uncore_type_0_2/event=1/,2287306455,100.00,,

Co-developed-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
v3:
 - Use fgets to read alias string from sysfs.
 - Resource cleanup.

v2:
 - No change.

 tools/perf/arch/x86/util/pmu.c | 129 ++++++++++++++++++++++++++++++++-
 tools/perf/util/parse-events.y |   3 +-
 tools/perf/util/pmu.c          |  26 ++++++-
 tools/perf/util/pmu.h          |   5 ++
 4 files changed, 158 insertions(+), 5 deletions(-)

diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
index d48d608517fd..9abba67cc62e 100644
--- a/tools/perf/arch/x86/util/pmu.c
+++ b/tools/perf/arch/x86/util/pmu.c
@@ -1,12 +1,29 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <string.h>
-
+#include <stdio.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <fcntl.h>
 #include <linux/stddef.h>
 #include <linux/perf_event.h>
+#include <linux/zalloc.h>
+#include <api/fs/fs.h>
+#include <errno.h>
 
 #include "../../../util/intel-pt.h"
 #include "../../../util/intel-bts.h"
 #include "../../../util/pmu.h"
+#include "../../../util/fncache.h"
+
+#define TEMPLATE_ALIAS	"%s/bus/event_source/devices/%s/alias"
+
+struct perf_pmu_alias_name {
+	char *name;
+	char *alias;
+	struct list_head list;
+};
+
+static LIST_HEAD(pmu_alias_name_list);
 
 struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
 {
@@ -18,3 +35,113 @@ struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu __mayb
 #endif
 	return NULL;
 }
+
+static int setup_pmu_alias_list(void)
+{
+	char path[PATH_MAX];
+	DIR *dir;
+	struct dirent *dent;
+	const char *sysfs = sysfs__mountpoint();
+	struct perf_pmu_alias_name *pmu;
+	char buf[MAX_PMU_NAME_LEN];
+	FILE *file;
+	int ret = 0;
+
+	if (!sysfs)
+		return -1;
+
+	snprintf(path, PATH_MAX,
+		 "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
+
+	dir = opendir(path);
+	if (!dir)
+		return -1;
+
+	while ((dent = readdir(dir))) {
+		if (!strcmp(dent->d_name, ".") ||
+		    !strcmp(dent->d_name, ".."))
+			continue;
+
+		snprintf(path, PATH_MAX,
+			 TEMPLATE_ALIAS, sysfs, dent->d_name);
+
+		if (!file_available(path))
+			continue;
+
+		file = fopen(path, "r");
+		if (!file)
+			continue;
+
+		if (!fgets(buf, sizeof(buf), file)) {
+			fclose(file);
+			continue;
+		}
+
+		fclose(file);
+
+		pmu = zalloc(sizeof(*pmu));
+		if (!pmu) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		/* Remove the last '\n' */
+		buf[strlen(buf) - 1] = 0;
+
+		pmu->alias = strdup(buf);
+		if (!pmu->alias)
+			goto mem_err;
+
+		pmu->name = strdup(dent->d_name);
+		if (!pmu->name)
+			goto mem_err;
+
+		list_add_tail(&pmu->list, &pmu_alias_name_list);
+		continue;
+mem_err:
+		ret = -ENOMEM;
+		free(pmu->alias);
+		free(pmu->name);
+		free(pmu);
+		break;
+	}
+
+	closedir(dir);
+	return ret;
+}
+
+static char *__pmu_find_real_name(const char *name)
+{
+	struct perf_pmu_alias_name *pmu;
+
+	list_for_each_entry(pmu, &pmu_alias_name_list, list) {
+		if (!strcmp(name, pmu->alias))
+			return strdup(pmu->name);
+	}
+
+	return strdup(name);
+}
+
+char *pmu_find_real_name(const char *name)
+{
+	static bool cached_list;
+
+	if (cached_list)
+		return __pmu_find_real_name(name);
+
+	setup_pmu_alias_list();
+	cached_list = true;
+
+	return __pmu_find_real_name(name);
+}
+
+char *pmu_find_alias_name(const char *name)
+{
+	struct perf_pmu_alias_name *pmu;
+
+	list_for_each_entry(pmu, &pmu_alias_name_list, list) {
+		if (!strcmp(name, pmu->name))
+			return strdup(pmu->alias);
+	}
+	return NULL;
+}
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 9321bd0e2f76..d94e48e1ff9b 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -316,7 +316,8 @@ event_pmu_name opt_pmu_config
 			if (!strncmp(name, "uncore_", 7) &&
 			    strncmp($1, "uncore_", 7))
 				name += 7;
-			if (!perf_pmu__match(pattern, name, $1)) {
+			if (!perf_pmu__match(pattern, name, $1) ||
+			    !perf_pmu__match(pattern, pmu->alias_name, $1)) {
 				if (parse_events_copy_term_list(orig_terms, &terms))
 					CLEANUP_YYABORT;
 				if (!parse_events_add_pmu(_parse_state, list, pmu->name, terms, true, false))
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 44b90d638ad5..cc9af7942e7b 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -944,13 +944,28 @@ static int pmu_max_precise(const char *name)
 	return max_precise;
 }
 
-static struct perf_pmu *pmu_lookup(const char *name)
+char * __weak
+pmu_find_real_name(const char *name)
+{
+	return strdup(name);
+}
+
+char * __weak
+pmu_find_alias_name(const char *name __maybe_unused)
+{
+	return NULL;
+}
+
+static struct perf_pmu *pmu_lookup(const char *lookup_name)
 {
 	struct perf_pmu *pmu;
+	char *name;
 	LIST_HEAD(format);
 	LIST_HEAD(aliases);
 	__u32 type;
 
+	name = pmu_find_real_name(lookup_name);
+
 	/*
 	 * The pmu data we store & need consists of the pmu
 	 * type value and format definitions. Load both right
@@ -973,7 +988,8 @@ static struct perf_pmu *pmu_lookup(const char *name)
 		return NULL;
 
 	pmu->cpus = pmu_cpumask(name);
-	pmu->name = strdup(name);
+	pmu->name = name;
+	pmu->alias_name = pmu_find_alias_name(name);
 	pmu->type = type;
 	pmu->is_uncore = pmu_is_uncore(name);
 	if (pmu->is_uncore)
@@ -1003,7 +1019,8 @@ static struct perf_pmu *pmu_find(const char *name)
 	struct perf_pmu *pmu;
 
 	list_for_each_entry(pmu, &pmus, list)
-		if (!strcmp(pmu->name, name))
+		if (!strcmp(pmu->name, name) ||
+		    (pmu->alias_name && !strcmp(pmu->alias_name, name)))
 			return pmu;
 
 	return NULL;
@@ -1898,6 +1915,9 @@ bool perf_pmu__has_hybrid(void)
 
 int perf_pmu__match(char *pattern, char *name, char *tok)
 {
+	if (!name)
+		return -1;
+
 	if (fnmatch(pattern, name, 0))
 		return -1;
 
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 926da483a141..f6ca9f6a06ef 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -21,6 +21,7 @@ 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"
+#define MAX_PMU_NAME_LEN 128
 
 struct perf_event_attr;
 
@@ -32,6 +33,7 @@ struct perf_pmu_caps {
 
 struct perf_pmu {
 	char *name;
+	char *alias_name;	/* PMU alias name */
 	char *id;
 	__u32 type;
 	bool selectable;
@@ -135,4 +137,7 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
 bool perf_pmu__has_hybrid(void);
 int perf_pmu__match(char *pattern, char *name, char *tok);
 
+char *pmu_find_real_name(const char *name);
+char *pmu_find_alias_name(const char *name);
+
 #endif /* __PMU_H */
-- 
2.27.0

Re: [PATCH v3 1/2] perf pmu: Add PMU alias support

[Riccardo Mancini]

Hi,

thanks for your quick revision. 

There is still one small memory issue with a variable not being freed, which I
noticed when running this patchset together with John's patchset.

On Fri, 2021-07-30 at 15:07 +0800, Jin Yao wrote:
> From: Kan Liang <kan.liang@linux.intel.com>
> 
> A perf uncore PMU may have two PMU names, a real name and an alias. The
> alias is exported at /sys/bus/event_source/devices/uncore_*/alias.
> The perf tool should support the alias as well.
> 
> Add alias_name in the struct perf_pmu to store the alias. For the PMU
> which doesn't have an alias. It's NULL.
> 
> Introduce two X86 specific functions to retrieve the real name and the
> alias separately.
> 
> Only go through the sysfs to retrieve the mapping between the real name
> and the alias once. The result is cached in a list, uncore_pmu_list.
> 
> Nothing changed for the other ARCHs.
> 
> With the patch, the perf tool can monitor the PMU with either the real
> name or the alias.
> 
> Use the real name,
>  $ perf stat -e uncore_cha_2/event=1/ -x,
>    4044879584,,uncore_cha_2/event=1/,2528059205,100.00,,
> 
> Use the alias,
>  $ perf stat -e uncore_type_0_2/event=1/ -x,
>    3659675336,,uncore_type_0_2/event=1/,2287306455,100.00,,
> 
> Co-developed-by: Jin Yao <yao.jin@linux.intel.com>
> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
> ---
> v3:
>  - Use fgets to read alias string from sysfs.
>  - Resource cleanup.
> 
> v2:
>  - No change.
> 
>  tools/perf/arch/x86/util/pmu.c | 129 ++++++++++++++++++++++++++++++++-
>  tools/perf/util/parse-events.y |   3 +-
>  tools/perf/util/pmu.c          |  26 ++++++-
>  tools/perf/util/pmu.h          |   5 ++
>  4 files changed, 158 insertions(+), 5 deletions(-)
> 
<SNIP>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 44b90d638ad5..cc9af7942e7b 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -944,13 +944,28 @@ static int pmu_max_precise(const char *name)
>         return max_precise;
>  }
>  
> -static struct perf_pmu *pmu_lookup(const char *name)
> +char * __weak
> +pmu_find_real_name(const char *name)
> +{
> +       return strdup(name);
> +}
> +
> +char * __weak
> +pmu_find_alias_name(const char *name __maybe_unused)
> +{
> +       return NULL;
> +}
> +
> +static struct perf_pmu *pmu_lookup(const char *lookup_name)
>  {
>         struct perf_pmu *pmu;
> +       char *name;
>         LIST_HEAD(format);
>         LIST_HEAD(aliases);
>         __u32 type;
>  
> +       name = pmu_find_real_name(lookup_name);

name is not freed if one of the following checks fails.

	/*
	 * The pmu data we store & need consists of the pmu
	 * type value and format definitions. Load both right
	 * now.
	 */
	if (pmu_format(name, &format))
		return NULL;

	/*
	 * Check the type first to avoid unnecessary work.
	 */
	if (pmu_type(name, &type))
		return NULL;

	if (pmu_aliases(name, &aliases))
		return NULL;

Thanks,
Riccardo


> @@ -973,7 +988,8 @@ static struct perf_pmu *pmu_lookup(const char *name)
>                 return NULL;
>  
>         pmu->cpus = pmu_cpumask(name);
> -       pmu->name = strdup(name);
> +       pmu->name = name;
> +       pmu->alias_name = pmu_find_alias_name(name);
>         pmu->type = type;
>         pmu->is_uncore = pmu_is_uncore(name);
>         if (pmu->is_uncore)
> @@ -1003,7 +1019,8 @@ static struct perf_pmu *pmu_find(const char *name)
>         struct perf_pmu *pmu;
>  
>         list_for_each_entry(pmu, &pmus, list)
> -               if (!strcmp(pmu->name, name))
> +               if (!strcmp(pmu->name, name) ||
> +                   (pmu->alias_name && !strcmp(pmu->alias_name, name)))
>                         return pmu;
>  
>         return NULL;
> @@ -1898,6 +1915,9 @@ bool perf_pmu__has_hybrid(void)
>  
>  int perf_pmu__match(char *pattern, char *name, char *tok)
>  {
> +       if (!name)
> +               return -1;
> +
>         if (fnmatch(pattern, name, 0))
>                 return -1;
>  
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 926da483a141..f6ca9f6a06ef 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -21,6 +21,7 @@ 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"
> +#define MAX_PMU_NAME_LEN 128
>  
>  struct perf_event_attr;
>  
> @@ -32,6 +33,7 @@ struct perf_pmu_caps {
>  
>  struct perf_pmu {
>         char *name;
> +       char *alias_name;       /* PMU alias name */
>         char *id;
>         __u32 type;
>         bool selectable;
> @@ -135,4 +137,7 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu,
> __u64 config,
>  bool perf_pmu__has_hybrid(void);
>  int perf_pmu__match(char *pattern, char *name, char *tok);
>  
> +char *pmu_find_real_name(const char *name);
> +char *pmu_find_alias_name(const char *name);
> +
>  #endif /* __PMU_H */

Re: [PATCH v3 1/2] perf pmu: Add PMU alias support

[Jin, Yao]

Hi Riccardo,

On 7/30/2021 4:28 PM, Riccardo Mancini wrote:
> Hi,
> 
> thanks for your quick revision.
> 
> There is still one small memory issue with a variable not being freed, which I
> noticed when running this patchset together with John's patchset.
> 
> On Fri, 2021-07-30 at 15:07 +0800, Jin Yao wrote:
>> From: Kan Liang <kan.liang@linux.intel.com>
>>
>> A perf uncore PMU may have two PMU names, a real name and an alias. The
>> alias is exported at /sys/bus/event_source/devices/uncore_*/alias.
>> The perf tool should support the alias as well.
>>
>> Add alias_name in the struct perf_pmu to store the alias. For the PMU
>> which doesn't have an alias. It's NULL.
>>
>> Introduce two X86 specific functions to retrieve the real name and the
>> alias separately.
>>
>> Only go through the sysfs to retrieve the mapping between the real name
>> and the alias once. The result is cached in a list, uncore_pmu_list.
>>
>> Nothing changed for the other ARCHs.
>>
>> With the patch, the perf tool can monitor the PMU with either the real
>> name or the alias.
>>
>> Use the real name,
>>   $ perf stat -e uncore_cha_2/event=1/ -x,
>>     4044879584,,uncore_cha_2/event=1/,2528059205,100.00,,
>>
>> Use the alias,
>>   $ perf stat -e uncore_type_0_2/event=1/ -x,
>>     3659675336,,uncore_type_0_2/event=1/,2287306455,100.00,,
>>
>> Co-developed-by: Jin Yao <yao.jin@linux.intel.com>
>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
>> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
>> ---
>> v3:
>>   - Use fgets to read alias string from sysfs.
>>   - Resource cleanup.
>>
>> v2:
>>   - No change.
>>
>>   tools/perf/arch/x86/util/pmu.c | 129 ++++++++++++++++++++++++++++++++-
>>   tools/perf/util/parse-events.y |   3 +-
>>   tools/perf/util/pmu.c          |  26 ++++++-
>>   tools/perf/util/pmu.h          |   5 ++
>>   4 files changed, 158 insertions(+), 5 deletions(-)
>>
> <SNIP>
>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>> index 44b90d638ad5..cc9af7942e7b 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -944,13 +944,28 @@ static int pmu_max_precise(const char *name)
>>          return max_precise;
>>   }
>>   
>> -static struct perf_pmu *pmu_lookup(const char *name)
>> +char * __weak
>> +pmu_find_real_name(const char *name)
>> +{
>> +       return strdup(name);
>> +}
>> +
>> +char * __weak
>> +pmu_find_alias_name(const char *name __maybe_unused)
>> +{
>> +       return NULL;
>> +}
>> +
>> +static struct perf_pmu *pmu_lookup(const char *lookup_name)
>>   {
>>          struct perf_pmu *pmu;
>> +       char *name;
>>          LIST_HEAD(format);
>>          LIST_HEAD(aliases);
>>          __u32 type;
>>   
>> +       name = pmu_find_real_name(lookup_name);
> 
> name is not freed if one of the following checks fails.
> 
> 	/*
> 	 * The pmu data we store & need consists of the pmu
> 	 * type value and format definitions. Load both right
> 	 * now.
> 	 */
> 	if (pmu_format(name, &format))
> 		return NULL;
> 
> 	/*
> 	 * Check the type first to avoid unnecessary work.
> 	 */
> 	if (pmu_type(name, &type))
> 		return NULL;
> 
> 	if (pmu_aliases(name, &aliases))
> 		return NULL;
> 
> Thanks,
> Riccardo
> 

Thanks so much for pointing this out. I also find I need to rebase the patch because it has some 
conflicts with John's patch. I will prepare v4 (which will be based on tmp.perf/urgent).

Thanks
Jin Yao

> 
>> @@ -973,7 +988,8 @@ static struct perf_pmu *pmu_lookup(const char *name)
>>                  return NULL;
>>   
>>          pmu->cpus = pmu_cpumask(name);
>> -       pmu->name = strdup(name);
>> +       pmu->name = name;
>> +       pmu->alias_name = pmu_find_alias_name(name);
>>          pmu->type = type;
>>          pmu->is_uncore = pmu_is_uncore(name);
>>          if (pmu->is_uncore)
>> @@ -1003,7 +1019,8 @@ static struct perf_pmu *pmu_find(const char *name)
>>          struct perf_pmu *pmu;
>>   
>>          list_for_each_entry(pmu, &pmus, list)
>> -               if (!strcmp(pmu->name, name))
>> +               if (!strcmp(pmu->name, name) ||
>> +                   (pmu->alias_name && !strcmp(pmu->alias_name, name)))
>>                          return pmu;
>>   
>>          return NULL;
>> @@ -1898,6 +1915,9 @@ bool perf_pmu__has_hybrid(void)
>>   
>>   int perf_pmu__match(char *pattern, char *name, char *tok)
>>   {
>> +       if (!name)
>> +               return -1;
>> +
>>          if (fnmatch(pattern, name, 0))
>>                  return -1;
>>   
>> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
>> index 926da483a141..f6ca9f6a06ef 100644
>> --- a/tools/perf/util/pmu.h
>> +++ b/tools/perf/util/pmu.h
>> @@ -21,6 +21,7 @@ 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"
>> +#define MAX_PMU_NAME_LEN 128
>>   
>>   struct perf_event_attr;
>>   
>> @@ -32,6 +33,7 @@ struct perf_pmu_caps {
>>   
>>   struct perf_pmu {
>>          char *name;
>> +       char *alias_name;       /* PMU alias name */
>>          char *id;
>>          __u32 type;
>>          bool selectable;
>> @@ -135,4 +137,7 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu,
>> __u64 config,
>>   bool perf_pmu__has_hybrid(void);
>>   int perf_pmu__match(char *pattern, char *name, char *tok);
>>   
>> +char *pmu_find_real_name(const char *name);
>> +char *pmu_find_alias_name(const char *name);
>> +
>>   #endif /* __PMU_H */
> 
> 

[PATCH v3 2/2] perf tests: Test for PMU alias

[Jin Yao]

A perf uncore PMU may have two PMU names, a real name and an alias
name. Add one test case to verify the real name and alias name having
the same effect.

Iterate the sysfs to get one event which has an alias and create
evlist by adding two evsels. Evsel1 is created by event and evsel2
is created by alias.

Test asserts:
evsel1->core.attr.type == evsel2->core.attr.type
evsel1->core.attr.config == evsel2->core.attr.config

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
v3:
 - Use fgets to read alias string from sysfs.
 - Resource cleanup.

v2:
 - New in v2.

 tools/perf/tests/parse-events.c | 92 +++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
index 56a7b6a14195..68c2e58861e1 100644
--- a/tools/perf/tests/parse-events.c
+++ b/tools/perf/tests/parse-events.c
@@ -6,6 +6,7 @@
 #include "tests.h"
 #include "debug.h"
 #include "pmu.h"
+#include "fncache.h"
 #include <dirent.h>
 #include <errno.h>
 #include <sys/types.h>
@@ -2190,9 +2191,91 @@ static int test_pmu_events(void)
 	return ret;
 }
 
+static bool test_alias(char **event, char **alias)
+{
+	char path[PATH_MAX];
+	DIR *dir;
+	struct dirent *dent;
+	const char *sysfs = sysfs__mountpoint();
+	char buf[128];
+	FILE *file;
+
+	if (!sysfs)
+		return false;
+
+	snprintf(path, PATH_MAX, "%s/bus/event_source/devices/", sysfs);
+	dir = opendir(path);
+	if (!dir)
+		return false;
+
+	while ((dent = readdir(dir))) {
+		if (!strcmp(dent->d_name, ".") ||
+		    !strcmp(dent->d_name, ".."))
+			continue;
+
+		snprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/alias",
+			 sysfs, dent->d_name);
+
+		if (!file_available(path))
+			continue;
+
+		file = fopen(path, "r");
+		if (!file)
+			continue;
+
+		if (!fgets(buf, sizeof(buf), file)) {
+			fclose(file);
+			continue;
+		}
+
+		/* Remove the last '\n' */
+		buf[strlen(buf) - 1] = 0;
+
+		fclose(file);
+		*event = strdup(dent->d_name);
+		*alias = strdup(buf);
+		closedir(dir);
+
+		if (*event == NULL || *alias == NULL) {
+			free(*event);
+			free(*alias);
+			return false;
+		}
+
+		return true;
+	}
+
+	closedir(dir);
+	return false;
+}
+
+static int test__checkevent_pmu_events_alias(struct evlist *evlist)
+{
+	struct evsel *evsel1 = evlist__first(evlist);
+	struct evsel *evsel2 = evlist__last(evlist);
+
+	TEST_ASSERT_VAL("wrong type", evsel1->core.attr.type == evsel2->core.attr.type);
+	TEST_ASSERT_VAL("wrong config", evsel1->core.attr.config == evsel2->core.attr.config);
+	return 0;
+}
+
+static int test_pmu_events_alias(char *event, char *alias)
+{
+	struct evlist_test e = { .id = 0, };
+	char name[2 * NAME_MAX + 20];
+
+	snprintf(name, sizeof(name), "%s/event=1/,%s/event=1/",
+		 event, alias);
+
+	e.name  = name;
+	e.check = test__checkevent_pmu_events_alias;
+	return test_event(&e);
+}
+
 int test__parse_events(struct test *test __maybe_unused, int subtest __maybe_unused)
 {
 	int ret1, ret2 = 0;
+	char *event, *alias;
 
 #define TEST_EVENTS(tests)				\
 do {							\
@@ -2217,6 +2300,15 @@ do {							\
 			return ret;
 	}
 
+	if (test_alias(&event, &alias)) {
+		int ret = test_pmu_events_alias(event, alias);
+
+		free(event);
+		free(alias);
+		if (ret)
+			return ret;
+	}
+
 	ret1 = test_terms(test__terms, ARRAY_SIZE(test__terms));
 	if (!ret2)
 		ret2 = ret1;
-- 
2.27.0