Commit edb217ff authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf pmu: Parse sysfs events directly from a file 



Rather than read a sysfs events file into a 256 byte char buffer, pass
the FILE* directly to the lex/yacc parser.

This avoids there being a maximum events file size.

While changing the API, constify some arguments to remove unnecessary
casts.

Allocating the read buffer decreases the performance of pmu-scan by
around 3%.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230824041330.266337-10-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3d504549

tools/perf/arch/x86/util/intel-pt.c

+1 −1
Original line number Diff line number Diff line
@@ -74,7 +74,7 @@ static int intel_pt_parse_terms_with_default(struct perf_pmu *pmu, 


	INIT_LIST_HEAD(terms);



	err = parse_events_terms(terms, str);

	err = parse_events_terms(terms, str, /*input=*/ NULL);

	if (err)

		goto out_free;

tools/perf/tests/parse-events.c

+1 −1
Original line number Diff line number Diff line
@@ -2472,7 +2472,7 @@ static int test_term(const struct terms_test *t) 


	INIT_LIST_HEAD(&terms);



	ret = parse_events_terms(&terms, t->str);

	ret = parse_events_terms(&terms, t->str, /*input=*/ NULL);

	if (ret) {

		pr_debug("failed to parse terms '%s', err %d\n",

			 t->str , ret);

tools/perf/util/parse-events.c

+12 −6
Original line number Diff line number Diff line
@@ -1715,6 +1715,7 @@ int parse_events_name(struct list_head *list, const char *name) 
}



static int parse_events__scanner(const char *str,

				 FILE *input,

				 struct parse_events_state *parse_state)

{

	YY_BUFFER_STATE buffer;
@@ -1725,7 +1726,10 @@ static int parse_events__scanner(const char *str, 
	if (ret)

		return ret;



	if (str)

		buffer = parse_events__scan_string(str, scanner);

	else

	        parse_events_set_in(input, scanner);



#ifdef PARSER_DEBUG

	parse_events_debug = 1;
@@ -1733,8 +1737,10 @@ static int parse_events__scanner(const char *str, 
#endif

	ret = parse_events_parse(parse_state, scanner);



	if (str) {

		parse_events__flush_buffer(buffer, scanner);

		parse_events__delete_buffer(buffer, scanner);

	}

	parse_events_lex_destroy(scanner);

	return ret;

}
@@ -1742,7 +1748,7 @@ static int parse_events__scanner(const char *str, 
/*

 * parse event config string, return a list of event terms.

 */

int parse_events_terms(struct list_head *terms, const char *str)

int parse_events_terms(struct list_head *terms, const char *str, FILE *input)

{

	struct parse_events_state parse_state = {

		.terms  = NULL,
@@ -1750,7 +1756,7 @@ int parse_events_terms(struct list_head *terms, const char *str) 
	};

	int ret;



	ret = parse_events__scanner(str, &parse_state);

	ret = parse_events__scanner(str, input, &parse_state);



	if (!ret) {

		list_splice(parse_state.terms, terms);
@@ -2001,7 +2007,7 @@ int __parse_events(struct evlist *evlist, const char *str, const char *pmu_filte 
	};

	int ret, ret2;



	ret = parse_events__scanner(str, &parse_state);

	ret = parse_events__scanner(str, /*input=*/ NULL, &parse_state);



	if (!ret && list_empty(&parse_state.list)) {

		WARN_ONCE(true, "WARNING: event parser found nothing\n");

tools/perf/util/parse-events.h

+2 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <stdbool.h>

#include <linux/types.h>

#include <linux/perf_event.h>

#include <stdio.h>

#include <string.h>



struct evsel;
@@ -42,7 +43,7 @@ static inline int parse_events(struct evlist *evlist, const char *str, 


int parse_event(struct evlist *evlist, const char *str);



int parse_events_terms(struct list_head *terms, const char *str);

int parse_events_terms(struct list_head *terms, const char *str, FILE *input);

int parse_filter(const struct option *opt, const char *str, int unset);

int exclude_perf(const struct option *opt, const char *arg, int unset);

tools/perf/util/pmu.c

+17 −31
Original line number Diff line number Diff line
@@ -280,7 +280,7 @@ int perf_pmu__convert_scale(const char *scale, char **end, double *sval) 
	return ret;

}



static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, int dirfd, char *name)

static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, int dirfd, const char *name)

{

	struct stat st;

	ssize_t sret;
@@ -312,7 +312,7 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, int dirfd, char * 
	return ret;

}



static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, int dirfd, char *name)

static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, int dirfd, const char *name)

{

	char path[PATH_MAX];

	ssize_t sret;
@@ -343,7 +343,7 @@ static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, int dirfd, char *n 
}



static int

perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, int dirfd, char *name)

perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, int dirfd, const char *name)

{

	char path[PATH_MAX];

	int fd;
@@ -361,7 +361,7 @@ perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, int dirfd, char *name) 
}



static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias,

				    int dirfd, char *name)

				    int dirfd, const char *name)

{

	char path[PATH_MAX];

	int fd;
@@ -454,8 +454,9 @@ static bool perf_pmu_merge_alias(struct perf_pmu_alias *newalias, 
	return false;

}



static int __perf_pmu__new_alias(struct list_head *list, int dirfd, char *name,

				 char *desc, char *val, const struct pmu_event *pe)

static int perf_pmu__new_alias(struct list_head *list, int dirfd, const char *name,

				const char *desc, const char *val, FILE *val_fd,

				const struct pmu_event *pe)

{

	struct parse_events_term *term;

	struct perf_pmu_alias *alias;
@@ -484,7 +485,7 @@ static int __perf_pmu__new_alias(struct list_head *list, int dirfd, char *name, 
	alias->snapshot = false;

	alias->deprecated = deprecated;



	ret = parse_events_terms(&alias->terms, val);

	ret = parse_events_terms(&alias->terms, val, val_fd);

	if (ret) {

		pr_err("Cannot parse alias %s: %d\n", val, ret);

		free(alias);
@@ -541,23 +542,6 @@ static int __perf_pmu__new_alias(struct list_head *list, int dirfd, char *name, 
	return 0;

}



static int perf_pmu__new_alias(struct list_head *list, int dirfd, char *name, FILE *file)

{

	char buf[256];

	int ret;



	ret = fread(buf, 1, sizeof(buf), file);

	if (ret == 0)

		return -EINVAL;



	buf[ret] = 0;



	/* Remove trailing newline from sysfs file */

	strim(buf);



	return __perf_pmu__new_alias(list, dirfd, name, NULL, buf, NULL);

}



static inline bool pmu_alias_info_file(char *name)

{

	size_t len;
@@ -613,7 +597,8 @@ static int pmu_aliases_parse(int dirfd, struct list_head *head) 
			continue;

		}



		if (perf_pmu__new_alias(head, dirfd, name, file) < 0)

		if (perf_pmu__new_alias(head, dirfd, name, /*desc=*/ NULL,

					/*val=*/ NULL, file, /*pe=*/ NULL) < 0)

			pr_debug("Cannot set up %s\n", name);

		fclose(file);

	}
@@ -866,7 +851,7 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe, 
	struct list_head *head = vdata;



	/* need type casts to override 'const' */

	__perf_pmu__new_alias(head, -1, (char *)pe->name, (char *)pe->desc, (char *)pe->event, pe);

	perf_pmu__new_alias(head, -1, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL, pe);

	return 0;

}
@@ -907,10 +892,11 @@ static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe, 


	if (!strcmp(pmu->id, pe->compat) &&

	    pmu_uncore_alias_match(pe->pmu, pmu->name)) {

		__perf_pmu__new_alias(idata->head, -1,

				      (char *)pe->name,

				      (char *)pe->desc,

				      (char *)pe->event,

		perf_pmu__new_alias(idata->head, -1,

				pe->name,

				pe->desc,

				pe->event,

				/*val_fd=*/ NULL,

				pe);

	}