2022-01-26 21:50:55

by Changbin Du

Subject: [PATCH] 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]>
---
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..26bff29ad277 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_evlist;
+ }
+ cmd_func = __cmd_latency;
+ break;
+ case PERF_FTRACE_NONE:
+ default:
+ pr_err("Invalid subcommand\n");
+ ret = -EINVAL;
+ goto out_delete_evlist;
+ }
+
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

2022-01-27 06:32:57

by Namhyung Kim

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

Hello,

On Wed, Jan 26, 2022 at 7:19 AM Changbin Du <[email protected]> wrote:
>
> The ftrace.target.system_wide must be set before invoking
> evlist__create_maps(), otherwise it has no effect.

Oh, right. Thanks for pointing that out.

>
> Fixes: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
> Signed-off-by: Changbin Du <[email protected]>
> ---
> 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..26bff29ad277 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;

We can move only this part after parse_options().

> + 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_evlist;

Otherwise, it should go to the out_delete_filters.

> + }
> + cmd_func = __cmd_latency;
> + break;
> + case PERF_FTRACE_NONE:
> + default:
> + pr_err("Invalid subcommand\n");
> + ret = -EINVAL;
> + goto out_delete_evlist;

Ditto.

Thanks,
Namhyung


> + }
> +
> 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
>

2022-01-28 00:30:09

by Changbin Du

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

On Wed, Jan 26, 2022 at 03:47:48PM -0800, Namhyung Kim wrote:
> Hello,
>
> On Wed, Jan 26, 2022 at 7:19 AM Changbin Du <[email protected]> wrote:
> >
> > The ftrace.target.system_wide must be set before invoking
> > evlist__create_maps(), otherwise it has no effect.
>
> Oh, right. Thanks for pointing that out.
>
> >
> > Fixes: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
> > Signed-off-by: Changbin Du <[email protected]>
> > ---
> > 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..26bff29ad277 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;
>
> We can move only this part after parse_options().
>
I prefer that all parsing works get be done first. :)

> > + 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_evlist;
>
> Otherwise, it should go to the out_delete_filters.
>
yes, will fix it.

> > + }
> > + cmd_func = __cmd_latency;
> > + break;
> > + case PERF_FTRACE_NONE:
> > + default:
> > + pr_err("Invalid subcommand\n");
> > + ret = -EINVAL;
> > + goto out_delete_evlist;
>
> Ditto.
>
okay.

> Thanks,
> Namhyung
>
>
> > + }
> > +
> > 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
> >

--
Cheers,
Changbin Du