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Commit 6b58e7f1 authored by Ulrich Drepper's avatar Ulrich Drepper Committed by Ingo Molnar
Browse files

perf tools: Avoid unnecessary work in directory lookups 



This patch improves some (common) inefficiencies in the
handling of directory lookups:

- not using the d_type information returned by the kernel

- constructing (absolute) paths for file operation even though
  directory-relative operations using the *at functions is
  possible

There are more places to fix but this is a start.

Signed-off-by: default avatarUlrich Drepper <drepper@redhat.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20090904193951.GB6186@ghostprotocols.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 849abde9

tools/perf/util/parse-events.c

+37 −31
Original line number Diff line number Diff line 


#include "../perf.h"

#include "util.h"

#include "../perf.h"

#include "parse-options.h"

#include "parse-events.h"

#include "exec_cmd.h"

#include "string.h"

#include "cache.h"



extern char *strcasestr(const char *haystack, const char *needle);



int					nr_counters;



struct perf_counter_attr		attrs[MAX_COUNTERS];
@@ -113,11 +111,9 @@ static unsigned long hw_cache_stat[C(MAX)] = { 
 [C(BPU)]	= (CACHE_READ),

};



#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st)	       \

#define for_each_subsystem(sys_dir, sys_dirent, sys_next)	       \

	while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next)	       \

	if (snprintf(file, MAXPATHLEN, "%s/%s", debugfs_path,	       	       \

			sys_dirent.d_name) &&		       		       \

	   (!stat(file, &st)) && (S_ISDIR(st.st_mode)) &&		       \

	if (sys_dirent.d_type == DT_DIR &&				       \

	   (strcmp(sys_dirent.d_name, ".")) &&				       \

	   (strcmp(sys_dirent.d_name, "..")))
@@ -136,11 +132,9 @@ static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir) 
	return 0;

}



#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next, file, st)    \

#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next)	       \

	while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next)        \

	if (snprintf(file, MAXPATHLEN, "%s/%s/%s", debugfs_path,	       \

		     sys_dirent.d_name, evt_dirent.d_name) &&		       \

	   (!stat(file, &st)) && (S_ISDIR(st.st_mode)) &&		       \

	if (evt_dirent.d_type == DT_DIR &&				       \

	   (strcmp(evt_dirent.d_name, ".")) &&				       \

	   (strcmp(evt_dirent.d_name, "..")) &&				       \

	   (!tp_event_has_id(&sys_dirent, &evt_dirent)))
@@ -163,9 +157,8 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config) 
	struct tracepoint_path *path = NULL;

	DIR *sys_dir, *evt_dir;

	struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;

	struct stat st;

	char id_buf[4];

	int fd;

	int sys_dir_fd, fd;

	u64 id;

	char evt_path[MAXPATHLEN];
@@ -175,17 +168,23 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config) 
	sys_dir = opendir(debugfs_path);

	if (!sys_dir)

		goto cleanup;

	sys_dir_fd = dirfd(sys_dir);



	for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {

		evt_dir = opendir(evt_path);

		if (!evt_dir)

			goto cleanup;

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,

								evt_path, st) {

			snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id",

				 debugfs_path, sys_dirent.d_name,

	for_each_subsystem(sys_dir, sys_dirent, sys_next) {

		int dfd = openat(sys_dir_fd, sys_dirent.d_name,

				 O_RDONLY|O_DIRECTORY), evt_dir_fd;

		if (dfd == -1)

			continue;

		evt_dir = fdopendir(dfd);

		if (!evt_dir) {

			close(dfd);

			continue;

		}

		evt_dir_fd = dirfd(evt_dir);

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {

			snprintf(evt_path, MAXPATHLEN, "%s/id",

				 evt_dirent.d_name);

			fd = open(evt_path, O_RDONLY);

			fd = openat(evt_dir_fd, evt_path, O_RDONLY);

			if (fd < 0)

				continue;

			if (read(fd, id_buf, sizeof(id_buf)) < 0) {
@@ -629,7 +628,7 @@ static void print_tracepoint_events(void) 
{

	DIR *sys_dir, *evt_dir;

	struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;

	struct stat st;

	int sys_dir_fd;

	char evt_path[MAXPATHLEN];



	if (valid_debugfs_mount(debugfs_path))
@@ -638,13 +637,20 @@ static void print_tracepoint_events(void) 
	sys_dir = opendir(debugfs_path);

	if (!sys_dir)

		goto cleanup;

	sys_dir_fd = dirfd(sys_dir);



	for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {

		evt_dir = opendir(evt_path);

		if (!evt_dir)

			goto cleanup;

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,

								evt_path, st) {

	for_each_subsystem(sys_dir, sys_dirent, sys_next) {

		int dfd = openat(sys_dir_fd, sys_dirent.d_name,

				 O_RDONLY|O_DIRECTORY), evt_dir_fd;

		if (dfd == -1)

			continue;

		evt_dir = fdopendir(dfd);

		if (!evt_dir) {

			close(dfd);

			continue;

		}

		evt_dir_fd = dirfd(evt_dir);

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {

			snprintf(evt_path, MAXPATHLEN, "%s:%s",

				 sys_dirent.d_name, evt_dirent.d_name);

			fprintf(stderr, "  %-40s [%s]\n", evt_path,