Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/3] perf ftrace: Add ftrace.tracer config option | From | Taeung Song <> | Date | Fri, 27 Jan 2017 12:52:13 +0900 |
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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 <jolsa@kernel.org> >> Cc: Namhyung Kim <namhyung@kernel.org> >> Signed-off-by: Taeung Song <treeze.taeung@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
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