perf probe: Show trace event definition

Add --definition/-D option for showing the trace-event definition in
stdout. This can be useful in debugging or combined with a shell script.

e.g.
  ----
  # perf probe --definition 'do_sys_open $params'
  p:probe/do_sys_open _text+2261728 dfd=%di:s32 filename=%si:u64 flags=%dx:s32 mode=%cx:u16
  ----

Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/147214226712.23638.2240534040014013658.stgit@devbox
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 f37d123d5dac82fe402709215827c1bf7e758d3d..56db4d40d27e5dbc66b952ca02a84991c16ee23f 100644 (file)
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -21,6 +21,8 @@ or
 'perf probe' [options] --vars='PROBEPOINT'
 or
 'perf probe' [options] --funcs
+or
+'perf probe' [options] --definition='PROBE' [...]
 
 DESCRIPTION
 -----------
@@ -96,6 +98,11 @@ OPTIONS
        can also list functions in a user space executable / shared library.
        This also can accept a FILTER rule argument.
 
+-D::
+--definition=::
+       Show trace-event definition converted from given probe-event instead
+       of write it into tracing/[k,u]probe_events.
+
 --filter=FILTER::
        (Only for --vars and --funcs) Set filter. FILTER is a combination of glob
        pattern, see FILTER PATTERN for detail.

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index ee5b42173ba374e066551f32eba24be8c863aebc..7a3d8c47ed2900647b140ab9d790d8aa9a1728b9 100644 (file)
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -326,6 +326,11 @@ static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs)
        if (ret < 0)
                goto out_cleanup;
 
+       if (params.command == 'D') {    /* it shows definition */
+               ret = show_probe_trace_events(pevs, npevs);
+               goto out_cleanup;
+       }
+
        ret = apply_perf_probe_events(pevs, npevs);
        if (ret < 0)
                goto out_cleanup;
@@ -454,6 +459,14 @@ out:
        return ret;
 }
 
+#ifdef HAVE_DWARF_SUPPORT
+#define PROBEDEF_STR   \
+       "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT [[NAME=]ARG ...]"
+#else
+#define PROBEDEF_STR   "[EVENT=]FUNC[+OFF|%return] [[NAME=]ARG ...]"
+#endif
+
+
 static int
 __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
 {
@@ -479,13 +492,7 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
                             opt_set_filter_with_command, DEFAULT_LIST_FILTER),
        OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
                     opt_set_filter_with_command),
-       OPT_CALLBACK('a', "add", NULL,
-#ifdef HAVE_DWARF_SUPPORT
-               "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT"
-               " [[NAME=]ARG ...]",
-#else
-               "[EVENT=]FUNC[+OFF|%return] [[NAME=]ARG ...]",
-#endif
+       OPT_CALLBACK('a', "add", NULL, PROBEDEF_STR,
                "probe point definition, where\n"
                "\t\tGROUP:\tGroup name (optional)\n"
                "\t\tEVENT:\tEvent name\n"
@@ -503,6 +510,9 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
                "\t\tARG:\tProbe argument (kprobe-tracer argument format.)\n",
 #endif
                opt_add_probe_event),
+       OPT_CALLBACK('D', "definition", NULL, PROBEDEF_STR,
+               "Show trace event definition of given traceevent for k/uprobe_events.",
+               opt_add_probe_event),
        OPT_BOOLEAN('f', "force", &probe_conf.force_add, "forcibly add events"
                    " with existing name"),
        OPT_CALLBACK('L', "line", NULL,
@@ -548,6 +558,7 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
 
        set_option_flag(options, 'a', "add", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'd', "del", PARSE_OPT_EXCLUSIVE);
+       set_option_flag(options, 'D', "definition", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'l', "list", PARSE_OPT_EXCLUSIVE);
 #ifdef HAVE_DWARF_SUPPORT
        set_option_flag(options, 'L', "line", PARSE_OPT_EXCLUSIVE);
@@ -644,6 +655,7 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
                }
                break;
        case 'a':
+       case 'D':
                /* Ensure the last given target is used */
                if (params.target && !params.target_used) {
                        pr_err("  Error: -x/-m must follow the probe definitions.\n");

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 0bed2ee1629259558a83bdc8e6620b9ea253b5f4..4a49cb8ce7abef79272f23648408a8e71af7aac8 100644 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -3207,6 +3207,52 @@ int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs)
        return 0;
 }
 
+static int show_probe_trace_event(struct probe_trace_event *tev)
+{
+       char *buf = synthesize_probe_trace_command(tev);
+
+       if (!buf) {
+               pr_debug("Failed to synthesize probe trace event.\n");
+               return -EINVAL;
+       }
+
+       /* Showing definition always go stdout */
+       printf("%s\n", buf);
+       free(buf);
+
+       return 0;
+}
+
+int show_probe_trace_events(struct perf_probe_event *pevs, int npevs)
+{
+       struct strlist *namelist = strlist__new(NULL, NULL);
+       struct probe_trace_event *tev;
+       struct perf_probe_event *pev;
+       int i, j, ret = 0;
+
+       if (!namelist)
+               return -ENOMEM;
+
+       for (j = 0; j < npevs && !ret; j++) {
+               pev = &pevs[j];
+               for (i = 0; i < pev->ntevs && !ret; i++) {
+                       tev = &pev->tevs[i];
+                       /* Skip if the symbol is out of .text or blacklisted */
+                       if (!tev->point.symbol && !pev->uprobes)
+                               continue;
+
+                       /* Set new name for tev (and update namelist) */
+                       ret = probe_trace_event__set_name(tev, pev,
+                                                         namelist, true);
+                       if (!ret)
+                               ret = show_probe_trace_event(tev);
+               }
+       }
+       strlist__delete(namelist);
+
+       return ret;
+}
+
 int apply_perf_probe_events(struct perf_probe_event *pevs, int npevs)
 {
        int i, ret = 0;

diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index f4f45db77c1c1ec59c3ee505f525f2b2561530ee..62094082d940594200e5a0a2b21af2774130395f 100644 (file)
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -147,6 +147,7 @@ int line_range__init(struct line_range *lr);
 int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
 int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs);
 int apply_perf_probe_events(struct perf_probe_event *pevs, int npevs);
+int show_probe_trace_events(struct perf_probe_event *pevs, int npevs);
 void cleanup_perf_probe_events(struct perf_probe_event *pevs, int npevs);
 int del_perf_probe_events(struct strfilter *filter);