2022-01-28 00:31:51

by Changbin Du

Subject: [PATCH v2] 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: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
Signed-off-by: Changbin Du <[email protected]>

---
v2: fix error handling.
---
tools/perf/builtin-ftrace.c | 45 ++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index dec24dc0e767..a8785dec5ca6 100644
--- 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);
--
2.32.0

2022-02-02 13:04:44

by Namhyung Kim

Subject: Re: [PATCH v2] perf/ftrace: system_wide collection is not effective by default

Hello,

On Thu, Jan 27, 2022 at 5:20 AM Changbin Du <[email protected]> wrote:
>
> The ftrace.target.system_wide must be set before invoking
> evlist__create_maps(), otherwise it has no effect.
>
> Fixes: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
> Signed-off-by: Changbin Du <[email protected]>

Acked-by: Namhyung Kim <[email protected]>

Thanks,
Namhyung

2022-02-09 10:11:19

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH v2] perf/ftrace: system_wide collection is not effective by default

Em Tue, Feb 01, 2022 at 08:47:49PM -0800, Namhyung Kim escreveu:
> Hello,
>
> On Thu, Jan 27, 2022 at 5:20 AM Changbin Du <[email protected]> wrote:
> >
> > The ftrace.target.system_wide must be set before invoking
> > evlist__create_maps(), otherwise it has no effect.
> >
> > Fixes: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
> > Signed-off-by: Changbin Du <[email protected]>
>
> Acked-by: Namhyung Kim <[email protected]>

Thanks, applied.

- Arnaldo