Re: [PATCH v6 1/2] perf pmu: Add PMU alias support
From: Jin, Yao
Date: Wed Sep 01 2021 - 21:21:55 EST
Hi Arnaldo,
On 9/2/2021 8:58 AM, Jin, Yao wrote:
Hi Arnaldo,
On 9/1/2021 9:57 PM, Arnaldo Carvalho de Melo wrote:
Em Wed, Sep 01, 2021 at 01:46:01PM +0800, Jin Yao escreveu:
<SNIP>
+++ b/tools/perf/arch/x86/util/pmu.c
<SNIP>
+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;
This isn't returning -ENOMEM like when zalloc() fails above. Also you're
mixing 'return -1' with 'return -ENOMEM', please be consistent. Please
find some -E errno for the !sysfs case, perhaps -ENODEV?
For opendir() error, can we just return -errno?
dir = opendir(path);
if (!dir)
return -errno;
+
+ pmu->name = strdup(dent->d_name);
+ if (!pmu->name)
+ goto mem_err;
+
+ list_add_tail(&pmu->list, &pmu_alias_name_list);
+ continue;
Don't we have a 'struct pmu' constructor/destructor pair? I.e. instead
of doing all this in an open coded way as above, why not have:
void pmu__delete(struct pmu *pmu)
{
if (!pmu)
return;
zfree(&pmu->name);
zfree(&pmu->alias);
free(pmu);
}
struct pmu *pmu__new(const char *name, const char *alias)
{
struct pmu *pmu = zalloc(sizeof(*pmu));
if (pmu) {
pmu->name = strdup(name);
if (!pmu->name)
goto out_delete;
pmu->alias = strdup(alias);
if (!pmu->alias)
goto out_delete;
}
return pmu;
out_err:
pmu__delete(pmu);
return NULL;
}
And then just:
pmu = pmu__new(dent->d_name, buf);
if (!pmu)
goto out_closedir;
list_add_tail(&pmu->list, &pmu_alias_name_list);
And then you don't need the 'continue', as this is the end of the loop
block.
That 'ret' probably should start with -ENOMEM and you end the function
with:
ret = 0;
out_closedir:
closedir(dir);
return ret;
}
Yes, using 'struct pmu' constructor/destructor is absolutely a good design.
I will follow this approach.
Strictly, it's not 'struct pmu' constructor/destructor. It's actually the 'struct
perf_pmu_alias_name' constructor/destructor.
We are both confused by the variable name 'pmu'. :(
Thanks
Jin Yao
The pmu__delete() should be used in perf's shutdown when running it
using memory leak detectors, when not using it, its ok to just leave it
as is to speed up the shutdown.
- Arnaldo
Yes, agree. I will create a separate patch to implement the 'struct pmu' constructor/destructor.
Thanks
Jin Yao
+mem_err:
+ 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 pmu->name;
+ }
+
+ return (char *)name;
+}
+
+char *pmu_find_real_name(const char *name)
+{
+ if (cached_list)
+ return __pmu_find_real_name(name);
+
+ setup_pmu_alias_list();
+ cached_list = true;
+
+ return __pmu_find_real_name(name);
+}
+
+static 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 pmu->alias;
+ }
+ return NULL;
+}
+
+char *pmu_find_alias_name(const char *name)
+{
+ if (cached_list)
+ return __pmu_find_alias_name(name);
+
+ setup_pmu_alias_list();
+ cached_list = true;
+
+ return __pmu_find_alias_name(name);
+}
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 6cdbee8a12e7..1a35915edf68 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -945,6 +945,18 @@ perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
return NULL;
}
+char * __weak
+pmu_find_real_name(const char *name)
+{
+ return (char *)name;
+}
+
+char * __weak
+pmu_find_alias_name(const char *name __maybe_unused)
+{
+ return NULL;
+}
+
static int pmu_max_precise(const char *name)
{
char path[PATH_MAX];
@@ -958,13 +970,15 @@ static int pmu_max_precise(const char *name)
return max_precise;
}
-static struct perf_pmu *pmu_lookup(const char *name)
+static struct perf_pmu *pmu_lookup(const char *lookup_name)
{
struct perf_pmu *pmu;
LIST_HEAD(format);
LIST_HEAD(aliases);
__u32 type;
+ char *name = pmu_find_real_name(lookup_name);
bool is_hybrid = perf_pmu__hybrid_mounted(name);
+ char *alias_name;
/*
* Check pmu name for hybrid and the pmu may be invalid in sysfs
@@ -995,6 +1009,16 @@ static struct perf_pmu *pmu_lookup(const char *name)
pmu->cpus = pmu_cpumask(name);
pmu->name = strdup(name);
+ if (!pmu->name)
+ goto err;
+
+ alias_name = pmu_find_alias_name(name);
+ if (alias_name) {
+ pmu->alias_name = strdup(alias_name);
+ if (!pmu->alias_name)
+ goto err;
+ }
+
pmu->type = type;
pmu->is_uncore = pmu_is_uncore(name);
if (pmu->is_uncore)
@@ -1017,15 +1041,22 @@ static struct perf_pmu *pmu_lookup(const char *name)
pmu->default_config = perf_pmu__get_default_config(pmu);
return pmu;
+err:
+ if (pmu->name)
+ free(pmu->name);
+ free(pmu);
+ return NULL;
}
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))
+ list_for_each_entry(pmu, &pmus, list) {
+ if (!strcmp(pmu->name, name) ||
+ (pmu->alias_name && !strcmp(pmu->alias_name, name)))
return pmu;
+ }
return NULL;
}
@@ -1919,6 +1950,9 @@ 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 033e8211c025..6b122f97acf3 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;
char *id;
__u32 type;
bool selectable;
@@ -136,4 +138,7 @@ 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 */
--
2.17.1