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perf pmu: Parse sysfs events directly from a file

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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: Ian 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2023-08-23 21:13:21 -07:00 committed by Arnaldo Carvalho de Melo
parent 3d5045492a
commit edb217ff14
5 changed files with 33 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/perf/arch/x86/util/intel-pt.c
View File

@ -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;

2
tools/perf/tests/parse-events.c
View File

@ -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);

18
tools/perf/util/parse-events.c
View File

@ -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;
buffer = parse_events__scan_string(str, scanner);
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);
parse_events__flush_buffer(buffer, scanner);
parse_events__delete_buffer(buffer, 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");

3
tools/perf/util/parse-events.h
View File

@ -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);

48
tools/perf/util/pmu.c
View File

@ -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;
}
@ -907,11 +892,12 @@ 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,
pe);
perf_pmu__new_alias(idata->head, -1,
pe->name,
pe->desc,
pe->event,
/*val_fd=*/ NULL,
pe);
}
return 0;