Message-ID: <ZuGo80t7uhlzG9BI@x1>
Date: Wed, 11 Sep 2024 11:28:03 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>,
	James Clark <james.clark@...aro.org>,
	Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>,
	Ravi Bangoria <ravi.bangoria@....com>,
	Weilin Wang <weilin.wang@...el.com>,
	Jing Zhang <renyu.zj@...ux.alibaba.com>,
	Xu Yang <xu.yang_2@....com>, Sandipan Das <sandipan.das@....com>,
	Benjamin Gray <bgray@...ux.ibm.com>,
	Athira Jajeev <atrajeev@...ux.vnet.ibm.com>,
	Howard Chu <howardchu95@...il.com>,
	Dominique Martinet <asmadeus@...ewreck.org>,
	Yang Jihong <yangjihong@...edance.com>,
	Colin Ian King <colin.i.king@...il.com>,
	Veronika Molnarova <vmolnaro@...hat.com>,
	"Dr. David Alan Gilbert" <linux@...blig.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Changbin Du <changbin.du@...wei.com>, Ze Gao <zegao2021@...il.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Clément Le Goffic <clement.legoffic@...s.st.com>,
	Sun Haiyong <sunhaiyong@...ngson.cn>,
	Junhao He <hejunhao3@...wei.com>,
	Tiezhu Yang <yangtiezhu@...ngson.cn>,
	Yicong Yang <yangyicong@...ilicon.com>,
	linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v1 02/15] perf pmus: Fake PMU clean up

On Fri, Sep 06, 2024 at 10:08:17PM -0700, Ian Rogers wrote:
> Rather than passing a fake PMU around, just pass that the fake PMU
> should be used - true when doing testing. Move the fake PMU into
> pmus.[ch] and try to abstract the PMU's properties in pmu.c, ie so
> there is less "if fake_pmu" in non-PMU code. Give the fake PMU a made
> up type number.

Cherry picked this one.

- Arnaldo
 
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
>  tools/perf/tests/parse-events.c |  4 ++--
>  tools/perf/tests/pmu-events.c   | 12 +++++-------
>  tools/perf/util/metricgroup.c   | 10 +++++-----
>  tools/perf/util/parse-events.c  | 33 +++++++++++++++++----------------
>  tools/perf/util/parse-events.h  |  8 ++++----
>  tools/perf/util/pmu.c           | 21 +++++++++++++++------
>  tools/perf/util/pmu.h           |  7 ++++---
>  tools/perf/util/pmus.c          | 11 +++++++++++
>  tools/perf/util/pmus.h          |  1 +
>  9 files changed, 64 insertions(+), 43 deletions(-)
> 
> diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
> index edc2adcf1bae..a9a77dfe0e97 100644
> --- a/tools/perf/tests/parse-events.c
> +++ b/tools/perf/tests/parse-events.c
> @@ -2500,7 +2500,7 @@ static int test_event(const struct evlist_test *e)
>  		return TEST_FAIL;
>  	}
>  	parse_events_error__init(&err);
> -	ret = __parse_events(evlist, e->name, /*pmu_filter=*/NULL, &err, /*fake_pmu=*/NULL,
> +	ret = __parse_events(evlist, e->name, /*pmu_filter=*/NULL, &err, /*fake_pmu=*/false,
>  			     /*warn_if_reordered=*/true, /*fake_tp=*/true);
>  	if (ret) {
>  		pr_debug("failed to parse event '%s', err %d\n", e->name, ret);
> @@ -2529,7 +2529,7 @@ static int test_event_fake_pmu(const char *str)
>  
>  	parse_events_error__init(&err);
>  	ret = __parse_events(evlist, str, /*pmu_filter=*/NULL, &err,
> -			     &perf_pmu__fake, /*warn_if_reordered=*/true,
> +			     /*fake_pmu=*/true, /*warn_if_reordered=*/true,
>  			     /*fake_tp=*/true);
>  	if (ret) {
>  		pr_debug("failed to parse event '%s', err %d\n",
> diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
> index ff3e7bc0a77f..db004d26fcb0 100644
> --- a/tools/perf/tests/pmu-events.c
> +++ b/tools/perf/tests/pmu-events.c
> @@ -819,8 +819,7 @@ static bool is_number(const char *str)
>  	return errno == 0 && end_ptr != str;
>  }
>  
> -static int check_parse_id(const char *id, struct parse_events_error *error,
> -			  struct perf_pmu *fake_pmu)
> +static int check_parse_id(const char *id, struct parse_events_error *error)
>  {
>  	struct evlist *evlist;
>  	int ret;
> @@ -841,7 +840,7 @@ static int check_parse_id(const char *id, struct parse_events_error *error,
>  	for (cur = strchr(dup, '@') ; cur; cur = strchr(++cur, '@'))
>  		*cur = '/';
>  
> -	ret = __parse_events(evlist, dup, /*pmu_filter=*/NULL, error, fake_pmu,
> +	ret = __parse_events(evlist, dup, /*pmu_filter=*/NULL, error, /*fake_pmu=*/true,
>  			     /*warn_if_reordered=*/true, /*fake_tp=*/false);
>  	free(dup);
>  
> @@ -855,7 +854,7 @@ static int check_parse_fake(const char *id)
>  	int ret;
>  
>  	parse_events_error__init(&error);
> -	ret = check_parse_id(id, &error, &perf_pmu__fake);
> +	ret = check_parse_id(id, &error);
>  	parse_events_error__exit(&error);
>  	return ret;
>  }
> @@ -1051,9 +1050,8 @@ static int test__parsing_fake_callback(const struct pmu_metric *pm,
>  }
>  
>  /*
> - * Parse all the metrics for current architecture,
> - * or all defined cpus via the 'fake_pmu'
> - * in parse_events.
> + * Parse all the metrics for current architecture, or all defined cpus via the
> + * 'fake_pmu' in parse_events.
>   */
>  static int test__parsing_fake(struct test_suite *test __maybe_unused,
>  			      int subtest __maybe_unused)
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 69f6a46402c3..4dff3e925a47 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -1436,7 +1436,7 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
>   * parse_ids - Build the event string for the ids and parse them creating an
>   *             evlist. The encoded metric_ids are decoded.
>   * @metric_no_merge: is metric sharing explicitly disabled.
> - * @fake_pmu: used when testing metrics not supported by the current CPU.
> + * @fake_pmu: use a fake PMU when testing metrics not supported by the current CPU.
>   * @ids: the event identifiers parsed from a metric.
>   * @modifier: any modifiers added to the events.
>   * @group_events: should events be placed in a weak group.
> @@ -1444,7 +1444,7 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
>   *               the overall list of metrics.
>   * @out_evlist: the created list of events.
>   */
> -static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
> +static int parse_ids(bool metric_no_merge, bool fake_pmu,
>  		     struct expr_parse_ctx *ids, const char *modifier,
>  		     bool group_events, const bool tool_events[PERF_TOOL_MAX],
>  		     struct evlist **out_evlist)
> @@ -1528,7 +1528,7 @@ static int parse_groups(struct evlist *perf_evlist,
>  			bool metric_no_threshold,
>  			const char *user_requested_cpu_list,
>  			bool system_wide,
> -			struct perf_pmu *fake_pmu,
> +			bool fake_pmu,
>  			struct rblist *metric_events_list,
>  			const struct pmu_metrics_table *table)
>  {
> @@ -1703,7 +1703,7 @@ int metricgroup__parse_groups(struct evlist *perf_evlist,
>  
>  	return parse_groups(perf_evlist, pmu, str, metric_no_group, metric_no_merge,
>  			    metric_no_threshold, user_requested_cpu_list, system_wide,
> -			    /*fake_pmu=*/NULL, metric_events, table);
> +			    /*fake_pmu=*/false, metric_events, table);
>  }
>  
>  int metricgroup__parse_groups_test(struct evlist *evlist,
> @@ -1717,7 +1717,7 @@ int metricgroup__parse_groups_test(struct evlist *evlist,
>  			    /*metric_no_threshold=*/false,
>  			    /*user_requested_cpu_list=*/NULL,
>  			    /*system_wide=*/false,
> -			    &perf_pmu__fake, metric_events, table);
> +			    /*fake_pmu=*/true, metric_events, table);
>  }
>  
>  struct metricgroup__has_metric_data {
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index fab01ba54e34..081ceff467f2 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1478,8 +1478,8 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state,
>  	}
>  
>  	/* Look for event names in the terms and rewrite into format based terms. */
> -	if (!parse_state->fake_pmu && perf_pmu__check_alias(pmu, &parsed_terms,
> -							    &info, &alias_rewrote_terms, err)) {
> +	if (perf_pmu__check_alias(pmu, &parsed_terms,
> +				  &info, &alias_rewrote_terms, err)) {
>  		parse_events_terms__exit(&parsed_terms);
>  		return -EINVAL;
>  	}
> @@ -1515,8 +1515,7 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state,
>  		return -ENOMEM;
>  	}
>  
> -	if (!parse_state->fake_pmu &&
> -	    perf_pmu__config(pmu, &attr, &parsed_terms, parse_state->error)) {
> +	if (perf_pmu__config(pmu, &attr, &parsed_terms, parse_state->error)) {
>  		free_config_terms(&config_terms);
>  		parse_events_terms__exit(&parsed_terms);
>  		return -EINVAL;
> @@ -1536,11 +1535,6 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state,
>  
>  	evsel->percore = config_term_percore(&evsel->config_terms);
>  
> -	if (parse_state->fake_pmu) {
> -		parse_events_terms__exit(&parsed_terms);
> -		return 0;
> -	}
> -
>  	parse_events_terms__exit(&parsed_terms);
>  	free((char *)evsel->unit);
>  	evsel->unit = strdup(info.unit);
> @@ -1616,13 +1610,13 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
>  	}
>  
>  	if (parse_state->fake_pmu) {
> -		if (!parse_events_add_pmu(parse_state, list, parse_state->fake_pmu, &parsed_terms,
> +		if (!parse_events_add_pmu(parse_state, list, perf_pmus__fake_pmu(), &parsed_terms,
>  					  /*auto_merge_stats=*/true)) {
>  			struct strbuf sb;
>  
>  			strbuf_init(&sb, /*hint=*/ 0);
>  			parse_events_terms__to_strbuf(&parsed_terms, &sb);
> -			pr_debug("%s -> %s/%s/\n", event_name, "fake_pmu", sb.buf);
> +			pr_debug("%s -> fake/%s/\n", event_name, sb.buf);
>  			strbuf_release(&sb);
>  			ok++;
>  		}
> @@ -1656,11 +1650,18 @@ int parse_events_multi_pmu_add_or_add_pmu(struct parse_events_state *parse_state
>  	INIT_LIST_HEAD(*listp);
>  
>  	/* Attempt to add to list assuming event_or_pmu is a PMU name. */
> -	pmu = parse_state->fake_pmu ?: perf_pmus__find(event_or_pmu);
> +	pmu = perf_pmus__find(event_or_pmu);
>  	if (pmu && !parse_events_add_pmu(parse_state, *listp, pmu, const_parsed_terms,
>  					/*auto_merge_stats=*/false))
>  		return 0;
>  
> +	if (parse_state->fake_pmu) {
> +		if (!parse_events_add_pmu(parse_state, *listp, perf_pmus__fake_pmu(),
> +					  const_parsed_terms,
> +					  /*auto_merge_stats=*/false))
> +			return 0;
> +	}
> +
>  	pmu = NULL;
>  	/* Failed to add, try wildcard expansion of event_or_pmu as a PMU name. */
>  	while ((pmu = perf_pmus__scan(pmu)) != NULL) {
> @@ -1961,8 +1962,8 @@ static int evsel__compute_group_pmu_name(struct evsel *evsel,
>  			}
>  		}
>  	}
> -	/* Assign the actual name taking care that the fake PMU lacks a name. */
> -	evsel->group_pmu_name = strdup(group_pmu_name ?: "fake");
> +	/* Record computed name. */
> +	evsel->group_pmu_name = strdup(group_pmu_name);
>  	return evsel->group_pmu_name ? 0 : -ENOMEM;
>  }
>  
> @@ -2124,7 +2125,7 @@ static int parse_events__sort_events_and_fix_groups(struct list_head *list)
>  }
>  
>  int __parse_events(struct evlist *evlist, const char *str, const char *pmu_filter,
> -		   struct parse_events_error *err, struct perf_pmu *fake_pmu,
> +		   struct parse_events_error *err, bool fake_pmu,
>  		   bool warn_if_reordered, bool fake_tp)
>  {
>  	struct parse_events_state parse_state = {
> @@ -2343,7 +2344,7 @@ int parse_events_option(const struct option *opt, const char *str,
>  
>  	parse_events_error__init(&err);
>  	ret = __parse_events(*args->evlistp, str, args->pmu_filter, &err,
> -			     /*fake_pmu=*/NULL, /*warn_if_reordered=*/true,
> +			     /*fake_pmu=*/false, /*warn_if_reordered=*/true,
>  			     /*fake_tp=*/false);
>  
>  	if (ret) {
> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> index b735cd9e0acf..bfbf391451d9 100644
> --- a/tools/perf/util/parse-events.h
> +++ b/tools/perf/util/parse-events.h
> @@ -31,14 +31,14 @@ int parse_events_option(const struct option *opt, const char *str, int unset);
>  int parse_events_option_new_evlist(const struct option *opt, const char *str, int unset);
>  __attribute__((nonnull(1, 2, 4)))
>  int __parse_events(struct evlist *evlist, const char *str, const char *pmu_filter,
> -		   struct parse_events_error *error, struct perf_pmu *fake_pmu,
> +		   struct parse_events_error *error, bool fake_pmu,
>  		   bool warn_if_reordered, bool fake_tp);
>  
>  __attribute__((nonnull(1, 2, 3)))
>  static inline int parse_events(struct evlist *evlist, const char *str,
>  			       struct parse_events_error *err)
>  {
> -	return __parse_events(evlist, str, /*pmu_filter=*/NULL, err, /*fake_pmu=*/NULL,
> +	return __parse_events(evlist, str, /*pmu_filter=*/NULL, err, /*fake_pmu=*/false,
>  			      /*warn_if_reordered=*/true, /*fake_tp=*/false);
>  }
>  
> @@ -150,8 +150,8 @@ struct parse_events_state {
>  	struct parse_events_terms *terms;
>  	/* Start token. */
>  	int			   stoken;
> -	/* Special fake PMU marker for testing. */
> -	struct perf_pmu		  *fake_pmu;
> +	/* Use the fake PMU marker for testing. */
> +	bool			   fake_pmu;
>  	/* Skip actual tracepoint processing for testing. */
>  	bool			   fake_tp;
>  	/* If non-null, when wildcard matching only match the given PMU. */
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 0b38c51bd6eb..50e2e7abffab 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -30,10 +30,6 @@
>  #include "util/evsel_config.h"
>  #include <regex.h>
>  
> -struct perf_pmu perf_pmu__fake = {
> -	.name = "fake",
> -};
> -
>  #define UNIT_MAX_LEN	31 /* max length for event unit name */
>  
>  enum event_source {
> @@ -1173,6 +1169,11 @@ struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *core_pm
>  	return pmu;
>  }
>  
> +static bool perf_pmu__is_fake(const struct perf_pmu *pmu)
> +{
> +	return pmu->type == PERF_PMU_TYPE_FAKE;
> +}
> +
>  void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu)
>  {
>  	struct perf_pmu_format *format;
> @@ -1183,7 +1184,7 @@ void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu)
>  	pmu->formats_checked = true;
>  
>  	/* fake pmu doesn't have format list */
> -	if (pmu == &perf_pmu__fake)
> +	if (perf_pmu__is_fake(pmu))
>  		return;
>  
>  	list_for_each_entry(format, &pmu->format, list) {
> @@ -1511,6 +1512,10 @@ int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr,
>  {
>  	bool zero = !!pmu->perf_event_attr_init_default;
>  
> +	/* Fake PMU doesn't have proper terms so nothing to configure in attr. */
> +	if (perf_pmu__is_fake(pmu))
> +		return 0;
> +
>  	return perf_pmu__config_terms(pmu, attr, head_terms, zero, err);
>  }
>  
> @@ -1619,6 +1624,10 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_
>  	info->scale    = 0.0;
>  	info->snapshot = false;
>  
> +	/* Fake PMU doesn't rewrite terms. */
> +	if (perf_pmu__is_fake(pmu))
> +		goto out;
> +
>  	list_for_each_entry_safe(term, h, &head_terms->terms, list) {
>  		alias = pmu_find_alias(pmu, term);
>  		if (!alias)
> @@ -1641,7 +1650,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_
>  		list_del_init(&term->list);
>  		parse_events_term__delete(term);
>  	}
> -
> +out:
>  	/*
>  	 * if no unit or scale found in aliases, then
>  	 * set defaults as for evsel
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index b2d3fd291f02..d6f702e55a05 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -36,6 +36,10 @@ struct perf_pmu_caps {
>  	struct list_head list;
>  };
>  
> +enum {
> +	PERF_PMU_TYPE_FAKE = 0xFFFFFFFF,
> +};
> +
>  /**
>   * struct perf_pmu
>   */
> @@ -173,9 +177,6 @@ struct perf_pmu {
>  	struct perf_mem_event *mem_events;
>  };
>  
> -/** @perf_pmu__fake: A special global PMU used for testing. */
> -extern struct perf_pmu perf_pmu__fake;
> -
>  struct perf_pmu_info {
>  	const char *unit;
>  	double scale;
> diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
> index 3fcabfd8fca1..864cbfa1f960 100644
> --- a/tools/perf/util/pmus.c
> +++ b/tools/perf/util/pmus.c
> @@ -720,3 +720,14 @@ struct perf_pmu *perf_pmus__add_test_pmu(int test_sysfs_dirfd, const char *name)
>  	 */
>  	return perf_pmu__lookup(&other_pmus, test_sysfs_dirfd, name, /*eager_load=*/true);
>  }
> +
> +struct perf_pmu *perf_pmus__fake_pmu(void)
> +{
> +	static struct perf_pmu fake = {
> +		.name = "fake",
> +		.type = PERF_PMU_TYPE_FAKE,
> +		.format = LIST_HEAD_INIT(fake.format),
> +	};
> +
> +	return &fake;
> +}
> diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
> index bdbff02324bb..e1742b56eec7 100644
> --- a/tools/perf/util/pmus.h
> +++ b/tools/perf/util/pmus.h
> @@ -30,5 +30,6 @@ bool perf_pmus__supports_extended_type(void);
>  char *perf_pmus__default_pmu_name(void);
>  
>  struct perf_pmu *perf_pmus__add_test_pmu(int test_sysfs_dirfd, const char *name);
> +struct perf_pmu *perf_pmus__fake_pmu(void);
>  
>  #endif /* __PMUS_H */
> -- 
> 2.46.0.469.g59c65b2a67-goog

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