perf probe: Show accessible local variables
Add -V (--vars) option for listing accessible local variables at given probe
point. This will help finding which local variables are available for event
arguments.
e.g.)
# perf probe -V call_timer_fn:23
Available variables at call_timer_fn:23
@<run_timer_softirq+345>
function_type* fn
int preempt_count
long unsigned int data
struct list_head work_list
struct list_head* head
struct timer_list* timer
struct tvec_base* base
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: <20101021101323.3542.40282.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/builtin-probe.c b/tools/perf/builtin-probe.c
index 199d5e1..91bb6cf 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -50,6 +50,8 @@
bool list_events;
bool force_add;
bool show_lines;
+ bool show_vars;
+ bool mod_events;
int nevents;
struct perf_probe_event events[MAX_PROBES];
struct strlist *dellist;
@@ -57,7 +59,6 @@
int max_probe_points;
} params;
-
/* Parse an event definition. Note that any error must die. */
static int parse_probe_event(const char *str)
{
@@ -92,6 +93,7 @@
len = 0;
for (i = 0; i < argc; i++)
len += sprintf(&buf[len], "%s ", argv[i]);
+ params.mod_events = true;
ret = parse_probe_event(buf);
free(buf);
return ret;
@@ -100,9 +102,10 @@
static int opt_add_probe_event(const struct option *opt __used,
const char *str, int unset __used)
{
- if (str)
+ if (str) {
+ params.mod_events = true;
return parse_probe_event(str);
- else
+ } else
return 0;
}
@@ -110,6 +113,7 @@
const char *str, int unset __used)
{
if (str) {
+ params.mod_events = true;
if (!params.dellist)
params.dellist = strlist__new(true, NULL);
strlist__add(params.dellist, str);
@@ -130,6 +134,25 @@
return ret;
}
+
+static int opt_show_vars(const struct option *opt __used,
+ const char *str, int unset __used)
+{
+ struct perf_probe_event *pev = ¶ms.events[params.nevents];
+ int ret;
+
+ if (!str)
+ return 0;
+
+ ret = parse_probe_event(str);
+ if (!ret && pev->nargs != 0) {
+ pr_err(" Error: '--vars' doesn't accept arguments.\n");
+ return -EINVAL;
+ }
+ params.show_vars = true;
+
+ return ret;
+}
#endif
static const char * const probe_usage[] = {
@@ -139,6 +162,7 @@
"perf probe --list",
#ifdef DWARF_SUPPORT
"perf probe --line 'LINEDESC'",
+ "perf probe --vars 'PROBEPOINT'",
#endif
NULL
};
@@ -180,6 +204,9 @@
OPT_CALLBACK('L', "line", NULL,
"FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]",
"Show source code lines.", opt_show_lines),
+ OPT_CALLBACK('V', "vars", NULL,
+ "FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",
+ "Show accessible variables on PROBEDEF", opt_show_vars),
OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
"file", "vmlinux pathname"),
OPT_STRING('s', "source", &symbol_conf.source_prefix,
@@ -217,7 +244,7 @@
usage_with_options(probe_usage, options);
if (params.list_events) {
- if (params.nevents != 0 || params.dellist) {
+ if (params.mod_events) {
pr_err(" Error: Don't use --list with --add/--del.\n");
usage_with_options(probe_usage, options);
}
@@ -225,6 +252,10 @@
pr_err(" Error: Don't use --list with --line.\n");
usage_with_options(probe_usage, options);
}
+ if (params.show_vars) {
+ pr_err(" Error: Don't use --list with --vars.\n");
+ usage_with_options(probe_usage, options);
+ }
ret = show_perf_probe_events();
if (ret < 0)
pr_err(" Error: Failed to show event list. (%d)\n",
@@ -234,9 +265,13 @@
#ifdef DWARF_SUPPORT
if (params.show_lines) {
- if (params.nevents != 0 || params.dellist) {
- pr_warning(" Error: Don't use --line with"
- " --add/--del.\n");
+ if (params.mod_events) {
+ pr_err(" Error: Don't use --line with"
+ " --add/--del.\n");
+ usage_with_options(probe_usage, options);
+ }
+ if (params.show_vars) {
+ pr_err(" Error: Don't use --line with --vars.\n");
usage_with_options(probe_usage, options);
}
@@ -245,6 +280,18 @@
pr_err(" Error: Failed to show lines. (%d)\n", ret);
return ret;
}
+ if (params.show_vars) {
+ if (params.mod_events) {
+ pr_err(" Error: Don't use --vars with"
+ " --add/--del.\n");
+ usage_with_options(probe_usage, options);
+ }
+ ret = show_available_vars(params.events, params.nevents,
+ params.max_probe_points);
+ if (ret < 0)
+ pr_err(" Error: Failed to show vars. (%d)\n", ret);
+ return ret;
+ }
#endif
if (params.dellist) {