Re: [PATCH 11/19] perf ftrace: add option '-u/--userstacktrace' to show userspace stacktrace

From: Arnaldo Carvalho de Melo
Date: Wed May 20 2020 - 17:07:46 EST


Em Sun, May 10, 2020 at 11:06:20PM +0800, Changbin Du escreveu:
> This adds an option ''-u/--userstacktrace' for function tracer to display
> userspace back trace.

Probably we should have this as a term, an option to --call-graph?

For --call-graph the way to suppress this is to ask for the event to be
in the kernel only, i.e. something like:

perf record -e cycles:k --call-graph

So perhaps we should have something like:

perf ftrace --call-graph

With some default, possibly a bit different than the other perf tools,
just including the kernel, and accepting:

perf ftrace --call-graph
perf ftrace --call-graph k
perf ftrace --call-graph u
perf ftrace --call-graph uk

- Arnaldo

> Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> ---
> 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 2ef5d1c4b23c..ab76ba66bd9e 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -40,6 +40,7 @@ struct perf_ftrace {
> struct list_head nograph_funcs;
> int graph_depth;
> bool func_stack_trace;
> + bool userstacktrace;
> bool nosleep_time;
> bool nofuncgraph_irqs;
> bool funcgraph_tail;
> @@ -197,6 +198,8 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
> write_tracing_option_file("funcgraph-proc", "0");
> write_tracing_option_file("funcgraph-abstime", "0");
> write_tracing_option_file("irq-info", "0");
> + write_tracing_option_file("userstacktrace", "0");
> + write_tracing_option_file("sym-userobj", "0");
> }
>
> static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
> @@ -287,6 +290,20 @@ static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace)
> return 0;
> }
>
> +static int set_tracing_userstacktrace(struct perf_ftrace *ftrace)
> +{
> + if (!ftrace->userstacktrace)
> + return 0;
> +
> + if (write_tracing_option_file("userstacktrace", "1") < 0)
> + return -1;
> +
> + if (write_tracing_option_file("sym-userobj", "1") < 0)
> + return -1;
> +
> + return 0;
> +}
> +
> static int reset_tracing_cpu(void)
> {
> struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
> @@ -482,6 +499,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
> goto out_reset;
> }
>
> + if (set_tracing_userstacktrace(ftrace) < 0) {
> + pr_err("failed to set tracing option userstacktrace\n");
> + goto out_reset;
> + }
> +
> if (set_tracing_filters(ftrace) < 0) {
> pr_err("failed to set tracing filters\n");
> goto out_reset;
> @@ -644,6 +666,8 @@ int cmd_ftrace(int argc, const char **argv)
> "do not trace given functions", parse_filter_func),
> OPT_BOOLEAN('s', "func-stack-trace", &ftrace.func_stack_trace,
> "Show kernel stack trace for function tracer"),
> + OPT_BOOLEAN('u', "userstacktrace", &ftrace.userstacktrace,
> + "Show stacktrace of the current user space thread"),
> OPT_CALLBACK_DEFAULT('G', "graph-funcs", &ftrace.graph_funcs, "func",
> "Set graph filter on given functions (imply to use function_graph tracer)",
> parse_filter_func, "*"),
> --
> 2.25.1
>

--

- Arnaldo