Commit b1d84af6 authored by Changbin Du's avatar Changbin Du Committed by Arnaldo Carvalho de Melo
Browse files

perf ftrace: Add support for tracing option 'func_stack_trace' 



This adds support to display call trace for function tracer. To do this,
just specify a '--func-opts call-graph' option.

Example:

  $ sudo perf ftrace -T vfs_read --func-opts call-graph
   iio-sensor-prox-855   [003]   6168.369657: vfs_read <-ksys_read
   iio-sensor-prox-855   [003]   6168.369677: <stack trace>
   => vfs_read
   => ksys_read
   => __x64_sys_read
   => do_syscall_64
   => entry_SYSCALL_64_after_hwframe
   ...

Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-9-changbin.du@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent a80abe2a

tools/perf/Documentation/perf-ftrace.txt

+4 −0
Original line number Diff line number Diff line
@@ -76,6 +76,10 @@ OPTIONS 
	specify multiple functions (or glob patterns).  It will be

	passed to 'set_ftrace_notrace' in tracefs.



--func-opts::

	List of options allowed to set:

	  call-graph - Display kernel stack trace for function tracer.



-G::

--graph-funcs=::

	Select function_graph tracer and set graph filter on the given

tools/perf/builtin-ftrace.c

+42 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include "util/cap.h"

#include "util/config.h"

#include "util/units.h"

#include "util/parse-sublevel-options.h"



#define DEFAULT_TRACER  "function_graph"
@@ -42,6 +43,7 @@ struct perf_ftrace { 
	int			graph_depth;

	unsigned long		percpu_buffer_size;

	bool			inherit;

	int			func_stack_trace;

};



struct filter_entry {
@@ -202,6 +204,7 @@ static void reset_tracing_filters(void); 
static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)

{

	write_tracing_option_file("function-fork", "0");

	write_tracing_option_file("func_stack_trace", "0");

}



static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
@@ -278,6 +281,17 @@ static int set_tracing_cpu(struct perf_ftrace *ftrace) 
	return set_tracing_cpumask(cpumap);

}



static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace)

{

	if (!ftrace->func_stack_trace)

		return 0;



	if (write_tracing_option_file("func_stack_trace", "1") < 0)

		return -1;



	return 0;

}



static int reset_tracing_cpu(void)

{

	struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
@@ -426,6 +440,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) 
		goto out_reset;

	}



	if (set_tracing_func_stack_trace(ftrace) < 0) {

		pr_err("failed to set tracing option func_stack_trace\n");

		goto out_reset;

	}



	if (set_tracing_filters(ftrace) < 0) {

		pr_err("failed to set tracing filters\n");

		goto out_reset;
@@ -598,6 +617,26 @@ static int parse_buffer_size(const struct option *opt, 
	return -1;

}



static int parse_func_tracer_opts(const struct option *opt,

				  const char *str, int unset)

{

	int ret;

	struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value;

	struct sublevel_option func_tracer_opts[] = {

		{ .name = "call-graph",	.value_ptr = &ftrace->func_stack_trace },

		{ .name = NULL, }

	};



	if (unset)

		return 0;



	ret = perf_parse_sublevel_options(str, func_tracer_opts);

	if (ret)

		return ret;



	return 0;

}



static void select_tracer(struct perf_ftrace *ftrace)

{

	bool graph = !list_empty(&ftrace->graph_funcs) ||
@@ -645,6 +684,9 @@ int cmd_ftrace(int argc, const char **argv) 
		     parse_filter_func),

	OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",

		     "do not trace given functions", parse_filter_func),

	OPT_CALLBACK(0, "func-opts", &ftrace, "options",

		     "function tracer options, available options: call-graph",

		     parse_func_tracer_opts),

	OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",

		     "trace given functions using function_graph tracer",

		     parse_filter_func),

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