perf ftrace: system_wide collection is not effective by default

The ftrace.target.system_wide must be set before invoking
evlist__create_maps(), otherwise it has no effect.

Fixes: 53be50282269b46c ("perf ftrace: Add 'latency' subcommand")
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220127132010.4836-1-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index dec24dc..a8785de 100644 (file)
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -1115,6 +1115,7 @@ enum perf_ftrace_subcommand {
 int cmd_ftrace(int argc, const char **argv)
 {
        int ret;
+       int (*cmd_func)(struct perf_ftrace *) = NULL;
        struct perf_ftrace ftrace = {
                .tracer = DEFAULT_TRACER,
                .target = { .uid = UINT_MAX, },
@@ -1221,6 +1222,28 @@ int cmd_ftrace(int argc, const char **argv)
                goto out_delete_filters;
        }
 
+       switch (subcmd) {
+       case PERF_FTRACE_TRACE:
+               if (!argc && target__none(&ftrace.target))
+                       ftrace.target.system_wide = true;
+               cmd_func = __cmd_ftrace;
+               break;
+       case PERF_FTRACE_LATENCY:
+               if (list_empty(&ftrace.filters)) {
+                       pr_err("Should provide a function to measure\n");
+                       parse_options_usage(ftrace_usage, options, "T", 1);
+                       ret = -EINVAL;
+                       goto out_delete_filters;
+               }
+               cmd_func = __cmd_latency;
+               break;
+       case PERF_FTRACE_NONE:
+       default:
+               pr_err("Invalid subcommand\n");
+               ret = -EINVAL;
+               goto out_delete_filters;
+       }
+
        ret = target__validate(&ftrace.target);
        if (ret) {
                char errbuf[512];
@@ -1248,27 +1271,7 @@ int cmd_ftrace(int argc, const char **argv)
                        goto out_delete_evlist;
        }
 
-       switch (subcmd) {
-       case PERF_FTRACE_TRACE:
-               if (!argc && target__none(&ftrace.target))
-                       ftrace.target.system_wide = true;
-               ret = __cmd_ftrace(&ftrace);
-               break;
-       case PERF_FTRACE_LATENCY:
-               if (list_empty(&ftrace.filters)) {
-                       pr_err("Should provide a function to measure\n");
-                       parse_options_usage(ftrace_usage, options, "T", 1);
-                       ret = -EINVAL;
-                       goto out_delete_evlist;
-               }
-               ret = __cmd_latency(&ftrace);
-               break;
-       case PERF_FTRACE_NONE:
-       default:
-               pr_err("Invalid subcommand\n");
-               ret = -EINVAL;
-               break;
-       }
+       ret = cmd_func(&ftrace);
 
 out_delete_evlist:
        evlist__delete(ftrace.evlist);