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perf ftrace: Add option '--inherit' to trace children processes

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This adds an option '--inherit' to allow us trace children
processes spawned by our target.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
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/20200808023141.14227-7-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Changbin Du 2020-08-08 10:31:29 +08:00 committed by Arnaldo Carvalho de Melo
parent 81523c1e57
commit 5b34747238
2 changed files with 41 additions and 0 deletions
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3
tools/perf/Documentation/perf-ftrace.txt
View File

@ -58,6 +58,9 @@ OPTIONS
Set the size of per-cpu tracing buffer, <size> is expected to
be a number with appended unit character - B/K/M/G.
--inherit::
Trace children processes spawned by our target.
-T::
--trace-funcs=::
Select function tracer and set function filter on the given

38
tools/perf/builtin-ftrace.c
View File

@ -41,6 +41,7 @@ struct perf_ftrace {
struct list_head nograph_funcs;
int graph_depth;
unsigned long percpu_buffer_size;
bool inherit;
};
struct filter_entry {
@ -182,9 +183,27 @@ static int write_tracing_file_int(const char *name, int value)
return 0;
}
static int write_tracing_option_file(const char *name, const char *val)
{
char *file;
int ret;
if (asprintf(&file, "options/%s", name) < 0)
return -1;
ret = __write_tracing_file(file, val, false);
free(file);
return ret;
}
static int reset_tracing_cpu(void);
static void reset_tracing_filters(void);
static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
{
write_tracing_option_file("function-fork", "0");
}
static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
{
if (write_tracing_file("tracing_on", "0") < 0)
@ -203,6 +222,7 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
return -1;
reset_tracing_filters();
reset_tracing_options(ftrace);
return 0;
}
@ -341,6 +361,17 @@ static int set_tracing_percpu_buffer_size(struct perf_ftrace *ftrace)
return 0;
}
static int set_tracing_trace_inherit(struct perf_ftrace *ftrace)
{
if (!ftrace->inherit)
return 0;
if (write_tracing_option_file("function-fork", "1") < 0)
return -1;
return 0;
}
static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
{
char *trace_file;
@ -410,6 +441,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_reset;
}
if (set_tracing_trace_inherit(ftrace) < 0) {
pr_err("failed to set tracing option function-fork\n");
goto out_reset;
}
if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
goto out_reset;
@ -618,6 +654,8 @@ int cmd_ftrace(int argc, const char **argv)
"Max depth for function graph tracer"),
OPT_CALLBACK('m', "buffer-size", &ftrace.percpu_buffer_size, "size",
"size of per cpu buffer", parse_buffer_size),
OPT_BOOLEAN(0, "inherit", &ftrace.inherit,
"trace children processes"),
OPT_END()
};