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Commit fb8c5a56 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Show accessible global variables 



Add --externs for allowing --vars to show accessible global (externally
defined) variables from a given probe point too.

This will give you a hint which globals can be accessible from the probe point.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101335.3542.31003.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c82ec0a2

tools/perf/Documentation/perf-probe.txt

+5 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ or 
or

'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'

or

'perf probe' --vars='PROBEPOINT'

'perf probe' [--externs] --vars='PROBEPOINT'



DESCRIPTION

-----------
@@ -64,6 +64,10 @@ OPTIONS 
	Show available local variables at given probe point. The argument

	syntax is same as PROBE SYNTAX, but NO ARGs.



--externs::

	(Only for --vars) Show external defined variables in addition to local

	variables.



-f::

--force::

	Forcibly add events with existing name.

tools/perf/builtin-probe.c

+6 −2
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ static struct { 
	bool force_add;

	bool show_lines;

	bool show_vars;

	bool show_ext_vars;

	bool mod_events;

	int nevents;

	struct perf_probe_event events[MAX_PROBES];
@@ -162,7 +163,7 @@ static const char * const probe_usage[] = { 
	"perf probe --list",

#ifdef DWARF_SUPPORT

	"perf probe --line 'LINEDESC'",

	"perf probe --vars 'PROBEPOINT'",

	"perf probe [--externs] --vars 'PROBEPOINT'",

#endif

	NULL

};
@@ -207,6 +208,8 @@ static const struct option options[] = { 
	OPT_CALLBACK('V', "vars", NULL,

		     "FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",

		     "Show accessible variables on PROBEDEF", opt_show_vars),

	OPT_BOOLEAN('\0', "externs", &params.show_ext_vars,

		    "Show external variables too (with --vars only)"),

	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,

		   "file", "vmlinux pathname"),

	OPT_STRING('s', "source", &symbol_conf.source_prefix,
@@ -287,7 +290,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
			usage_with_options(probe_usage, options);

		}

		ret = show_available_vars(params.events, params.nevents,

					  params.max_probe_points);

					  params.max_probe_points,

					  params.show_ext_vars);

		if (ret < 0)

			pr_err("  Error: Failed to show vars. (%d)\n", ret);

		return ret;

tools/perf/util/probe-event.c

+4 −4
Original line number Diff line number Diff line
@@ -379,7 +379,7 @@ int show_line_range(struct line_range *lr) 
}



static int show_available_vars_at(int fd, struct perf_probe_event *pev,

				  int max_vls)

				  int max_vls, bool externs)

{

	char *buf;

	int ret, i;
@@ -391,7 +391,7 @@ static int show_available_vars_at(int fd, struct perf_probe_event *pev, 
		return -EINVAL;

	pr_debug("Searching variables at %s\n", buf);



	ret = find_available_vars_at(fd, pev, &vls, max_vls);

	ret = find_available_vars_at(fd, pev, &vls, max_vls, externs);

	if (ret > 0) {

		/* Some variables were found */

		fprintf(stdout, "Available variables at %s\n", buf);
@@ -421,7 +421,7 @@ static int show_available_vars_at(int fd, struct perf_probe_event *pev, 


/* Show available variables on given probe point */

int show_available_vars(struct perf_probe_event *pevs, int npevs,

			int max_vls)

			int max_vls, bool externs)

{

	int i, fd, ret = 0;
@@ -438,7 +438,7 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs, 
	setup_pager();



	for (i = 0; i < npevs && ret >= 0; i++)

		ret = show_available_vars_at(fd, &pevs[i], max_vls);

		ret = show_available_vars_at(fd, &pevs[i], max_vls, externs);



	close(fd);

	return ret;

tools/perf/util/probe-event.h

+1 −1
Original line number Diff line number Diff line
@@ -122,7 +122,7 @@ extern int del_perf_probe_events(struct strlist *dellist); 
extern int show_perf_probe_events(void);

extern int show_line_range(struct line_range *lr);

extern int show_available_vars(struct perf_probe_event *pevs, int npevs,

			       int max_probe_points);

			       int max_probe_points, bool externs);





/* Maximum index number of event-name postfix */

tools/perf/util/probe-finder.c

+21 −5
Original line number Diff line number Diff line
@@ -1312,12 +1312,13 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data) 
						af->pf.fb_ops, NULL);

		if (ret == 0) {

			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);

			pr_debug2("Add new var: %s\n", buf);

			if (ret > 0)

				strlist__add(vl->vars, buf);

		}

	}



	if (dwarf_haspc(die_mem, af->pf.addr))

	if (af->child && dwarf_haspc(die_mem, af->pf.addr))

		return DIE_FIND_CB_CONTINUE;

	else

		return DIE_FIND_CB_SIBLING;
@@ -1329,8 +1330,8 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf) 
	struct available_var_finder *af =

			container_of(pf, struct available_var_finder, pf);

	struct variable_list *vl;

	Dwarf_Die die_mem;

	int ret;

	Dwarf_Die die_mem, *scopes = NULL;

	int ret, nscopes;



	/* Check number of tevs */

	if (af->nvls == af->max_vls) {
@@ -1351,8 +1352,22 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf) 
	vl->vars = strlist__new(true, NULL);

	if (vl->vars == NULL)

		return -ENOMEM;

	af->child = true;

	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);



	/* Find external variables */

	if (!af->externs)

		goto out;

	/* Don't need to search child DIE for externs. */

	af->child = false;

	nscopes = dwarf_getscopes_die(sp_die, &scopes);

	while (nscopes-- > 1)

		die_find_child(&scopes[nscopes], collect_variables_cb,

			       (void *)af, &die_mem);

	if (scopes)

		free(scopes);



out:

	if (strlist__empty(vl->vars)) {

		strlist__delete(vl->vars);

		vl->vars = NULL;
@@ -1363,11 +1378,12 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf) 


/* Find available variables at given probe point */

int find_available_vars_at(int fd, struct perf_probe_event *pev,

			   struct variable_list **vls, int max_vls)

			   struct variable_list **vls, int max_vls,

			   bool externs)

{

	struct available_var_finder af = {

			.pf = {.pev = pev, .callback = add_available_vars},

			.max_vls = max_vls};

			.max_vls = max_vls, .externs = externs};

	int ret;



	/* Allocate result vls array */