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Date: Fri, 13 Aug 2021 09:59:10 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: John Garry <john.garry@...wei.com>, acme@...nel.org,
jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...ux.intel.com
Cc: Linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com,
rickyman7@...il.com, Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [PATCH v4 1/2] perf pmu: Add PMU alias support
Hi John,
On 8/12/2021 8:14 PM, John Garry wrote:
> perf pmu: Add x86 PMU alias support
>
>> +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);
>
> I would not expect a function which does a "find" to duplicate the name.
>
> Same goes for all the other places which does similar.
>
Yes, you are right. Jiri has the similar comment for the name duplicating here. We will still keep
the 'pmu->name = strdup(name);' in pmu_lookup() in v5.
>> + }
>> + 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 fc683bc41715..796a4be752f4 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -946,6 +946,18 @@ perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
>> return NULL;
>> }
>> +char * __weak
>> +pmu_find_real_name(const char *name)
>> +{
>> + return strdup(name);
>> +}
>
> That's not finding anything.
>
Will just return name in non-x86 implementation.
pmu_find_real_name(const char *name)
{
return 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];
>> @@ -959,19 +971,25 @@ 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;
>> + struct perf_pmu *pmu = NULL;
>> LIST_HEAD(format);
>> LIST_HEAD(aliases);
>> __u32 type;
>> - bool is_hybrid = perf_pmu__hybrid_mounted(name);
>> + bool is_hybrid;
>> + char *name = pmu_find_real_name(lookup_name);
>> +
>> + if (!name)
>> + return NULL;
>> +
>> + is_hybrid = perf_pmu__hybrid_mounted(name);
>> /*
>> * Check pmu name for hybrid and the pmu may be invalid in sysfs
>> */
>> if (!strncmp(name, "cpu_", 4) && !is_hybrid)
>> - return NULL;
>> + goto out;
>> /*
>> * The pmu data we store & need consists of the pmu
>> @@ -979,23 +997,24 @@ static struct perf_pmu *pmu_lookup(const char *name)
>> * now.
>> */
>> if (pmu_format(name, &format))
>> - return NULL;
>> + goto out;
>> /*
>> * Check the type first to avoid unnecessary work.
>> */
>> if (pmu_type(name, &type))
>> - return NULL;
>> + goto out;
>> if (pmu_aliases(name, &aliases))
>> - return NULL;
>> + goto out;
>> pmu = zalloc(sizeof(*pmu));
>> if (!pmu)
>> - return NULL;
>> + goto out;
>> 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)
>> @@ -1017,6 +1036,10 @@ static struct perf_pmu *pmu_lookup(const char *name)
>> pmu->default_config = perf_pmu__get_default_config(pmu);
>> +out:
>> + if (!pmu)
>> + free(name);
>
> I don't understand this. There are lots of places this function can fail , but we don't free
> memories allocated previously - why just free this one?
>
That's because it's only introduced by my patch (duplicating name). :)
But if we keep 'pmu->name = strdup(name)' in pmu_lookup(), I'm OK to keep original code/behavior.
>> +
>> return pmu;
>> }
>> @@ -1025,7 +1048,8 @@ 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;
>
> I'd be inclined to use {} for the list_for_each_entry() call
>
OK, I will add {}, thanks!
>> return NULL;
>> @@ -1920,6 +1944,9 @@ 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 */
>
> useless comment
>
OK, remove it :)
Thanks
Jin Yao
>> 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 */
>>
>
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