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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 72f5d9e2143283e1aef829dee755bb2863604f07..148c178a35aae2b7878a923170ddd191965e59da 100644 (file)
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -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.

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index c777bec2846678bb6521ca82ce0ef5471ec15ede..bdf60cfdf70f77175282ac84edad1afb49fe656f 100644 (file)
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -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;

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 83192a59f02a435cb7cc77153a9d497c0f11c1c6..82b0976e2053dcb6a77a7c76ce4c9be12deb0770 100644 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -379,7 +379,7 @@ end:
 }
 
 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;

diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 83130f634f01178f26cf1bfd05db989dc1b394c9..c74b1fd2c1fa6f7c1c6bb5d3b22c1eb94e3fdec2 100644 (file)
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -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 */

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 986027fa495f8d373e3af0f7e174a1de421bbd01..a274fd0c143eaa997e57ccdd3f34b006848f89dc 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -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 */

diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index baffd25f39c9b7eaf9683c17194e7c0d811ed8c2..516912a04011ed9f024c943a8f63276fcdf43d5c 100644 (file)
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -30,7 +30,8 @@ extern int find_line_range(int fd, struct line_range *lr);
 
 /* Find available variables */
 extern int find_available_vars_at(int fd, struct perf_probe_event *pev,
-                                 struct variable_list **vls, int max_points);
+                                 struct variable_list **vls, int max_points,
+                                 bool externs);
 
 #include <dwarf.h>
 #include <libdw.h>
@@ -70,6 +71,8 @@ struct available_var_finder {
        struct variable_list    *vls;           /* Found variable lists */
        int                     nvls;           /* Number of variable lists */
        int                     max_vls;        /* Max no. of variable lists */
+       bool                    externs;        /* Find external vars too */
+       bool                    child;          /* Search child scopes */
 };
 
 struct line_finder {