On 01/27/2017 03:58 AM, Arnaldo Carvalho de Melo wrote:
Em Thu, Jan 26, 2017 at 06:35:38PM +0900, Taeung Song escreveu:
Currently perf ftrace command will select 'function_graph' or 'function'.
So add ftrace.tracer config option to select tracer
# cat ~/.perfconfig
[ftrace]
tracer = function
# perf ftrace usleep 123456 | head -10
<...>-14450 [002] d... 10089.284231: finish_task_switch <-__schedule
<...>-14450 [002] .... 10089.284232: finish_wait <-pipe_wait
<...>-14450 [002] .... 10089.284232: mutex_lock <-pipe_wait
<...>-14450 [002] .... 10089.284232: _cond_resched <-mutex_lock
<...>-14450 [002] .... 10089.284233: generic_pipe_buf_confirm <-pipe_read
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Signed-off-by: Taeung Song <treeze.tae...@gmail.com>
---
tools/perf/builtin-ftrace.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 414444d..8df5416 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -17,6 +17,7 @@
#include "evlist.h"
#include "target.h"
#include "thread_map.h"
+#include "util/config.h"
#define DEFAULT_TRACER "function_graph"
@@ -198,6 +199,23 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int
argc, const char **argv)
return done ? 0 : -1;
}
+static int perf_ftrace_config(const char *var, const char *value, void *cb)
+{
+ struct perf_ftrace *ftrace = cb;
+
+ if (!strcmp(var, "ftrace.tracer")) {
+ if (!strcmp(value, "function_graph"))
+ ftrace->tracer = DEFAULT_TRACER;
+ else if (!strcmp(value, "function"))
+ ftrace->tracer = "function";
+ else
+ return -1;
Please warn the user for invalid values and either just say that it is
ignoring that setting or return -1 to make perf_config() return that,
then make cmd_ftrace() check the return of perf_config() and bail out if
you're not ignoring the config value.
I think its better to do a: "pr_err()" in that "return -1" branch and
make 'perf ftrace' fail, so that the user can fix its config before
proceeding.
Arnaldo,
I modified this patch as below.
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 8df5416..00e228f 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -208,8 +208,11 @@ static int perf_ftrace_config(const char *var,
const char *value, void *cb)
ftrace->tracer = DEFAULT_TRACER;
else if (!strcmp(value, "function"))
ftrace->tracer = "function";
- else
+ else {
+ pr_err("Please select function_graph(default)"
+ "or function to use tracer.\n");
return -1;
+ }
return 0;
}
@@ -236,7 +239,9 @@ int cmd_ftrace(int argc, const char **argv, const
char *prefix __maybe_unused)
OPT_END()
};
- perf_config(perf_ftrace_config, &ftrace);
+ ret = perf_config(perf_ftrace_config, &ftrace);
+ if (ret < 0)
+ return -1;
argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
PARSE_OPT_STOP_AT_NON_OPTION);
But if setting wrong config value,
existing error message is printed in perf_config().
So output can be printed as follows
1) Two error messages
# perf ftrace usleep 123456
Please select function_graph(default)or function to use tracer.
Error: wrong config key-value pair ftrace.tracer=functionds
2) Or only one error message in perf_config()
(if we don't "pr_err()" in that "return -1" branch)
# perf ftrace usleep 123456
Error: wrong config key-value pair ftrace.tracer=functionds
Which do you like better, 1) or 2) ?
Thanks,
Taeung
