* [PATCH] perf ftrace: Detect whether ftrace is enabled on system
@ 2024-09-10 3:36 Changbin Du
2024-09-11 9:45 ` James Clark
0 siblings, 1 reply; 3+ messages in thread
From: Changbin Du @ 2024-09-10 3:36 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim
Cc: Mark Rutland, Alexander Shishkin, Jiri Olsa, Ian Rogers,
Adrian Hunter, Liang, Kan, linux-perf-users, linux-kernel,
Changbin Du
To make error messages more accurate, this change detects whether ftrace is
enabled on system by checking trace file "set_ftrace_pid".
Before:
~ # perf ftrace
failed to reset ftrace
After:
~ # perf ftrace
ftrace is not supported on this system
Signed-off-by: Changbin Du <changbin.du@huawei.com>
---
tools/perf/builtin-ftrace.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index eb30c8eca488..e1dc2768bc0f 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -1112,6 +1112,24 @@ static int parse_graph_tracer_opts(const struct option *opt,
return 0;
}
+static bool is_ftrace_supported(void)
+{
+ char *file;
+ bool supported = false;
+
+ file = get_tracing_file("set_ftrace_pid");
+ if (!file) {
+ pr_debug("cannot get tracing file set_ftrace_pid\n");
+ return false;
+ }
+
+ if (!access(file, F_OK))
+ supported = true;
+
+ put_tracing_file(file);
+ return supported;
+}
+
enum perf_ftrace_subcommand {
PERF_FTRACE_NONE,
PERF_FTRACE_TRACE,
@@ -1254,6 +1272,12 @@ int cmd_ftrace(int argc, const char **argv)
goto out_delete_filters;
}
+ if (!is_ftrace_supported()) {
+ pr_err("ftrace is not supported on this system\n");
+ ret = -ENOTSUP;
+ goto out_delete_filters;
+ }
+
ret = target__validate(&ftrace.target);
if (ret) {
char errbuf[512];
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] perf ftrace: Detect whether ftrace is enabled on system
2024-09-10 3:36 [PATCH] perf ftrace: Detect whether ftrace is enabled on system Changbin Du
@ 2024-09-11 9:45 ` James Clark
2024-09-11 10:00 ` duchangbin
0 siblings, 1 reply; 3+ messages in thread
From: James Clark @ 2024-09-11 9:45 UTC (permalink / raw)
To: Changbin Du
Cc: Mark Rutland, Alexander Shishkin, Jiri Olsa, Ian Rogers,
Adrian Hunter, Liang, Kan, linux-perf-users, linux-kernel,
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim
On 10/09/2024 04:36, Changbin Du wrote:
> To make error messages more accurate, this change detects whether ftrace is
> enabled on system by checking trace file "set_ftrace_pid".
>
> Before:
> ~ # perf ftrace
> failed to reset ftrace
>
> After:
> ~ # perf ftrace
> ftrace is not supported on this system
>
> Signed-off-by: Changbin Du <changbin.du@huawei.com>
> ---
> tools/perf/builtin-ftrace.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index eb30c8eca488..e1dc2768bc0f 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -1112,6 +1112,24 @@ static int parse_graph_tracer_opts(const struct option *opt,
> return 0;
> }
>
> +static bool is_ftrace_supported(void)
> +{
> + char *file;
> + bool supported = false;
> +
> + file = get_tracing_file("set_ftrace_pid");
> + if (!file) {
> + pr_debug("cannot get tracing file set_ftrace_pid\n");
> + return false;
> + }
> +
> + if (!access(file, F_OK))
> + supported = true;
> +
> + put_tracing_file(file);
> + return supported;
> +}
> +
> enum perf_ftrace_subcommand {
> PERF_FTRACE_NONE,
> PERF_FTRACE_TRACE,
> @@ -1254,6 +1272,12 @@ int cmd_ftrace(int argc, const char **argv)
> goto out_delete_filters;
> }
>
> + if (!is_ftrace_supported()) {
> + pr_err("ftrace is not supported on this system\n");
> + ret = -ENOTSUP;
> + goto out_delete_filters;
> + }
> +
Very minor nit, but you could probably put this earlier next to
check_ftrace_capable(). It didn't look like it used any of the config or
parsing results.
Either way:
Reviewed-by: James Clark <james.clark@linaro.org>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] perf ftrace: Detect whether ftrace is enabled on system
2024-09-11 9:45 ` James Clark
@ 2024-09-11 10:00 ` duchangbin
0 siblings, 0 replies; 3+ messages in thread
From: duchangbin @ 2024-09-11 10:00 UTC (permalink / raw)
To: James Clark
Cc: duchangbin, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, Liang, Kan,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim
On Wed, Sep 11, 2024 at 10:45:16AM +0100, James Clark wrote:
>
>
> On 10/09/2024 04:36, Changbin Du wrote:
> > To make error messages more accurate, this change detects whether ftrace is
> > enabled on system by checking trace file "set_ftrace_pid".
> >
> > Before:
> > ~ # perf ftrace
> > failed to reset ftrace
> >
> > After:
> > ~ # perf ftrace
> > ftrace is not supported on this system
> >
> > Signed-off-by: Changbin Du <changbin.du@huawei.com>
> > ---
> > tools/perf/builtin-ftrace.c | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > index eb30c8eca488..e1dc2768bc0f 100644
> > --- a/tools/perf/builtin-ftrace.c
> > +++ b/tools/perf/builtin-ftrace.c
> > @@ -1112,6 +1112,24 @@ static int parse_graph_tracer_opts(const struct option *opt,
> > return 0;
> > }
> > +static bool is_ftrace_supported(void)
> > +{
> > + char *file;
> > + bool supported = false;
> > +
> > + file = get_tracing_file("set_ftrace_pid");
> > + if (!file) {
> > + pr_debug("cannot get tracing file set_ftrace_pid\n");
> > + return false;
> > + }
> > +
> > + if (!access(file, F_OK))
> > + supported = true;
> > +
> > + put_tracing_file(file);
> > + return supported;
> > +}
> > +
> > enum perf_ftrace_subcommand {
> > PERF_FTRACE_NONE,
> > PERF_FTRACE_TRACE,
> > @@ -1254,6 +1272,12 @@ int cmd_ftrace(int argc, const char **argv)
> > goto out_delete_filters;
> > }
> > + if (!is_ftrace_supported()) {
> > + pr_err("ftrace is not supported on this system\n");
> > + ret = -ENOTSUP;
> > + goto out_delete_filters;
> > + }
> > +
>
> Very minor nit, but you could probably put this earlier next to
> check_ftrace_capable(). It didn't look like it used any of the config or
> parsing results.
>
Thansk, I will rebase this on perf-tools-next branch.
> Either way:
>
> Reviewed-by: James Clark <james.clark@linaro.org>
--
Cheers,
Changbin Du
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-09-10 3:36 [PATCH] perf ftrace: Detect whether ftrace is enabled on system Changbin Du
2024-09-11 9:45 ` James Clark
2024-09-11 10:00 ` duchangbin
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