Re: [PATCH v7 1/2] perf pmu: Add PMU alias support
From: Arnaldo Carvalho de Melo
Date: Fri Sep 03 2021 - 07:52:08 EST
Em Fri, Sep 03, 2021 at 08:38:23AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Sep 02, 2021 at 02:59:54PM +0800, Jin Yao escreveu:
> > From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxxx>
> > Co-developed-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > ---
> > v7:
> > - Create 'struct perf_pmu_alias_name' constructor/destructor.
> > - Return '-errno' if opendir() is failed.
>
> Thanks for addressing those, I did a v8 here with the changes described
> in my Committer notes below, please holler if you disagree.
Please take a look at my tmp.perf/core branch, it has the patch below
and the test one plus what I'm about to push to Linus.
- Arnaldo
> commit 13d60ba0738b0532edab3e1492b2005d36ba0802
> Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Date: Thu Sep 2 14:59:54 2021 +0800
>
> perf pmu: Add PMU alias support
>
> 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,,
>
> Committer notes:
>
> Rename 'struct perf_pmu_alias_name' to 'pmu_alias', the 'perf_' prefix
> should be used for libperf, things inside just tools/perf/ are being
> moved away from that prefix.
>
> Also 'pmu_alias' is shorter and reflects the abstraction.
>
> Also don't use 'pmu' as the name for variables for that type, we should
> use that for the 'struct perf_pmu' variables, avoiding confusion. Use
> 'pmu_alias' for 'struct pmu_alias' variables.
>
> Co-developed-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> Co-developed-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: John Garry <john.garry@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Riccardo Mancini <rickyman7@xxxxxxxxx>
> Link: http://lore.kernel.org/lkml/20210902065955.1299-2-yao.jin@xxxxxxxxxxxxxxx
> Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>
> diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
> index d48d608517fd2732..74d69db1ea99df17 100644
> --- a/tools/perf/arch/x86/util/pmu.c
> +++ b/tools/perf/arch/x86/util/pmu.c
> @@ -1,12 +1,30 @@
> // 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 pmu_alias {
> + char *name;
> + char *alias;
> + struct list_head list;
> +};
> +
> +static LIST_HEAD(pmu_alias_name_list);
> +static bool cached_list;
>
> struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu __maybe_unused)
> {
> @@ -18,3 +36,138 @@ struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu __mayb
> #endif
> return NULL;
> }
> +
> +static void pmu_alias__delete(struct pmu_alias *pmu_alias)
> +{
> + if (!pmu_alias)
> + return;
> +
> + zfree(&pmu_alias->name);
> + zfree(&pmu_alias->alias);
> + free(pmu_alias);
> +}
> +
> +static struct pmu_alias *pmu_alias__new(char *name, char *alias)
> +{
> + struct pmu_alias *pmu_alias = zalloc(sizeof(*pmu_alias));
> +
> + if (pmu_alias) {
> + pmu_alias->name = strdup(name);
> + if (!pmu_alias->name)
> + goto out_delete;
> +
> + pmu_alias->alias = strdup(alias);
> + if (!pmu_alias->alias)
> + goto out_delete;
> + }
> + return pmu_alias;
> +
> +out_delete:
> + pmu_alias__delete(pmu_alias);
> + return NULL;
> +}
> +
> +static int setup_pmu_alias_list(void)
> +{
> + char path[PATH_MAX];
> + DIR *dir;
> + struct dirent *dent;
> + const char *sysfs = sysfs__mountpoint();
> + struct pmu_alias *pmu_alias;
> + char buf[MAX_PMU_NAME_LEN];
> + FILE *file;
> + int ret = -ENOMEM;
> +
> + if (!sysfs)
> + return -1;
> +
> + snprintf(path, PATH_MAX,
> + "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
> +
> + dir = opendir(path);
> + if (!dir)
> + return -errno;
> +
> + 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);
> +
> + /* Remove the last '\n' */
> + buf[strlen(buf) - 1] = 0;
> +
> + pmu_alias = pmu_alias__new(dent->d_name, buf);
> + if (!pmu_alias)
> + goto close_dir;
> +
> + list_add_tail(&pmu_alias->list, &pmu_alias_name_list);
> + }
> +
> + ret = 0;
> +
> +close_dir:
> + closedir(dir);
> + return ret;
> +}
> +
> +static char *__pmu_find_real_name(const char *name)
> +{
> + struct pmu_alias *pmu_alias;
> +
> + list_for_each_entry(pmu_alias, &pmu_alias_name_list, list) {
> + if (!strcmp(name, pmu_alias->alias))
> + return pmu_alias->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 pmu_alias *pmu_alias;
> +
> + list_for_each_entry(pmu_alias, &pmu_alias_name_list, list) {
> + if (!strcmp(name, pmu_alias->name))
> + return pmu_alias->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 9321bd0e2f76321a..d94e48e1ff9b22dd 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 5f486ccb6fe67b58..bdabd62170d2cf1f 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 5133bc45603492f7..394898b07fd9874b 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -22,6 +22,7 @@ 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;
>
> @@ -33,6 +34,7 @@ struct perf_pmu_caps {
>
> struct perf_pmu {
> char *name;
> + char *alias_name;
> char *id;
> __u32 type;
> bool selectable;
> @@ -140,4 +142,7 @@ int perf_pmu__match(char *pattern, char *name, char *tok);
> int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
> struct perf_cpu_map **mcpus_ptr,
> struct perf_cpu_map **ucpus_ptr);
> +
> +char *pmu_find_real_name(const char *name);
> +char *pmu_find_alias_name(const char *name);
> #endif /* __PMU_H */
--
- Arnaldo