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Commit 5beeded1 authored by Jason Baron's avatar Jason Baron Committed by Peter Zijlstra
Browse files

perf_counter: Detect debugfs location 



If "/sys/kernel/debug" is not a debugfs mount point, search for the debugfs
filesystem in /proc/mounts, but also allows the user to specify
'--debugfs-dir=blah' or set the environment variable: 'PERF_DEBUGFS_DIR'

Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
[ also made it probe "/debug" by default ]
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090721181629.GA3094@redhat.com>
parent f6bdafef

tools/perf/perf.c

+76 −1
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include "util/cache.h"

#include "util/quote.h"

#include "util/run-command.h"

#include "util/parse-events.h"

#include "util/string.h"



const char perf_usage_string[] =

	"perf [--version] [--help] COMMAND [ARGS]";
@@ -25,6 +27,8 @@ struct pager_config { 
	int val;

};



static char debugfs_mntpt[MAXPATHLEN];



static int pager_command_config(const char *var, const char *value, void *data)

{

	struct pager_config *c = data;
@@ -56,6 +60,15 @@ static void commit_pager_choice(void) { 
	}

}



static void set_debugfs_path(void)

{

	char *path;



	path = getenv(PERF_DEBUGFS_ENVIRONMENT);

	snprintf(debugfs_path, MAXPATHLEN, "%s/%s", path ?: debugfs_mntpt,

		 "tracing/events");

}



static int handle_options(const char*** argv, int* argc, int* envchanged)

{

	int handled = 0;
@@ -122,6 +135,22 @@ static int handle_options(const char*** argv, int* argc, int* envchanged) 
			setenv(PERF_WORK_TREE_ENVIRONMENT, cmd + 12, 1);

			if (envchanged)

				*envchanged = 1;

		} else if (!strcmp(cmd, "--debugfs-dir")) {

			if (*argc < 2) {

				fprintf(stderr, "No directory given for --debugfs-dir.\n");

				usage(perf_usage_string);

			}

			strncpy(debugfs_mntpt, (*argv)[1], MAXPATHLEN);

			debugfs_mntpt[MAXPATHLEN - 1] = '\0';

			if (envchanged)

				*envchanged = 1;

			(*argv)++;

			(*argc)--;

		} else if (!prefixcmp(cmd, "--debugfs-dir=")) {

			strncpy(debugfs_mntpt, cmd + 14, MAXPATHLEN);

			debugfs_mntpt[MAXPATHLEN - 1] = '\0';

			if (envchanged)

				*envchanged = 1;

		} else {

			fprintf(stderr, "Unknown option: %s\n", cmd);

			usage(perf_usage_string);
@@ -228,6 +257,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv) 
	if (use_pager == -1 && p->option & USE_PAGER)

		use_pager = 1;

	commit_pager_choice();

	set_debugfs_path();



	status = p->fn(argc, argv, prefix);

	if (status)
@@ -346,6 +376,49 @@ static int run_argv(int *argcp, const char ***argv) 
	return done_alias;

}



/* mini /proc/mounts parser: searching for "^blah /mount/point debugfs" */

static void get_debugfs_mntpt(void)

{

	FILE *file;

	char fs_type[100];

	char debugfs[MAXPATHLEN];



	/*

	 * try the standard location

	 */

	if (valid_debugfs_mount("/sys/kernel/debug/") == 0) {

		strcpy(debugfs_mntpt, "/sys/kernel/debug/");

		return;

	}



	/*

	 * try the sane location

	 */

	if (valid_debugfs_mount("/debug/") == 0) {

		strcpy(debugfs_mntpt, "/debug/");

		return;

	}



	/*

	 * give up and parse /proc/mounts

	 */

	file = fopen("/proc/mounts", "r");

	if (file == NULL)

		return;



	while (fscanf(file, "%*s %"

		      STR(MAXPATHLEN)

		      "s %99s %*s %*d %*d\n",

		      debugfs, fs_type) == 2) {

		if (strcmp(fs_type, "debugfs") == 0)

			break;

	}

	fclose(file);

	if (strcmp(fs_type, "debugfs") == 0) {

		strncpy(debugfs_mntpt, debugfs, MAXPATHLEN);

		debugfs_mntpt[MAXPATHLEN - 1] = '\0';

	}

}



int main(int argc, const char **argv)

{
@@ -354,7 +427,8 @@ int main(int argc, const char **argv) 
	cmd = perf_extract_argv0_path(argv[0]);

	if (!cmd)

		cmd = "perf-help";



	/* get debugfs mount point from /proc/mounts */

	get_debugfs_mntpt();

	/*

	 * "perf-xxxx" is the same as "perf xxxx", but we obviously:

	 *
@@ -377,6 +451,7 @@ int main(int argc, const char **argv) 
	argc--;

	handle_options(&argv, &argc, NULL);

	commit_pager_choice();

	set_debugfs_path();

	if (argc > 0) {

		if (!prefixcmp(argv[0], "--"))

			argv[0] += 2;

tools/perf/util/cache.h

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#define PERFATTRIBUTES_FILE ".perfattributes"

#define INFOATTRIBUTES_FILE "info/attributes"

#define ATTRIBUTE_MACRO_PREFIX "[attr]"

#define PERF_DEBUGFS_ENVIRONMENT "PERF_DEBUGFS_DIR"



typedef int (*config_fn_t)(const char *, const char *, void *);

extern int perf_default_config(const char *, const char *, void *);

tools/perf/util/parse-events.c

+17 −16
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include "parse-events.h"

#include "exec_cmd.h"

#include "string.h"

#include "cache.h"



extern char *strcasestr(const char *haystack, const char *needle);
@@ -12,8 +13,6 @@ int nr_counters; 


struct perf_counter_attr		attrs[MAX_COUNTERS];



static char default_debugfs_path[] = "/sys/kernel/debug/tracing/events";



struct event_symbol {

	u8	type;

	u64	config;
@@ -21,6 +20,8 @@ struct event_symbol { 
	char	*alias;

};



char debugfs_path[MAXPATHLEN];



#define CHW(x) .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_##x

#define CSW(x) .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_##x
@@ -114,7 +115,7 @@ static unsigned long hw_cache_stat[C(MAX)] = { 


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

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

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

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

			sys_dirent.d_name) &&		       		       \

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

	   (strcmp(sys_dirent.d_name, ".")) &&				       \
@@ -122,7 +123,7 @@ static unsigned long hw_cache_stat[C(MAX)] = { 


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

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

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

	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)) &&		       \

	   (strcmp(evt_dirent.d_name, ".")) &&				       \
@@ -130,11 +131,11 @@ static unsigned long hw_cache_stat[C(MAX)] = { 


#define MAX_EVENT_LENGTH 30



static int valid_debugfs_mount(void)

int valid_debugfs_mount(const char *debugfs)

{

	struct statfs st_fs;



	if (statfs(default_debugfs_path, &st_fs) < 0)

	if (statfs(debugfs, &st_fs) < 0)

		return -ENOENT;

	else if (st_fs.f_type != (long) DEBUGFS_MAGIC)

		return -ENOENT;
@@ -152,10 +153,10 @@ static char *tracepoint_id_to_name(u64 config) 
	u64 id;

	char evt_path[MAXPATHLEN];



	if (valid_debugfs_mount())

	if (valid_debugfs_mount(debugfs_path))

		return "unkown";



	sys_dir = opendir(default_debugfs_path);

	sys_dir = opendir(debugfs_path);

	if (!sys_dir)

		goto cleanup;
@@ -166,7 +167,7 @@ static char *tracepoint_id_to_name(u64 config) 
		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,

								evt_path, st) {

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

				 default_debugfs_path, sys_dirent.d_name,

				 debugfs_path, sys_dirent.d_name,

				 evt_dirent.d_name);

			fd = open(evt_path, O_RDONLY);

			if (fd < 0)
@@ -363,7 +364,7 @@ static int parse_tracepoint_event(const char **strp, 
	u64 id;

	char evt_path[MAXPATHLEN];



	if (valid_debugfs_mount())

	if (valid_debugfs_mount(debugfs_path))

		return 0;



	evt_name = strchr(*strp, ':');
@@ -381,7 +382,7 @@ static int parse_tracepoint_event(const char **strp, 
	if (evt_length >= MAX_EVENT_LENGTH)

		return 0;



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

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

		 sys_name, evt_name);

	fd = open(evt_path, O_RDONLY);

	if (fd < 0)
@@ -568,10 +569,10 @@ static void print_tracepoint_events(void) 
	struct stat st;

	char evt_path[MAXPATHLEN];



	if (valid_debugfs_mount())

	if (valid_debugfs_mount(debugfs_path))

		return;



	sys_dir = opendir(default_debugfs_path);

	sys_dir = opendir(debugfs_path);

	if (!sys_dir)

		goto cleanup;

tools/perf/util/parse-events.h

+5 −0
Original line number Diff line number Diff line
@@ -3,6 +3,8 @@ 
 * Parse symbolic events/counts passed in as options:

 */



struct option;



extern int			nr_counters;



extern struct perf_counter_attr attrs[MAX_COUNTERS];
@@ -15,3 +17,6 @@ extern int parse_events(const struct option *opt, const char *str, int unset); 


extern void print_events(void);



extern char debugfs_path[];

extern int valid_debugfs_mount(const char *debugfs);

tools/perf/util/string.h

+3 −0
Original line number Diff line number Diff line
@@ -5,4 +5,7 @@ 


int hex2u64(const char *ptr, u64 *val);



#define _STR(x) #x

#define STR(x) _STR(x)



#endif