From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753982AbdA0D7C (ORCPT ); Thu, 26 Jan 2017 22:59:02 -0500 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33755 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934AbdA0D7B (ORCPT ); Thu, 26 Jan 2017 22:59:01 -0500 Subject: Re: [PATCH 2/3] perf ftrace: Add ftrace.tracer config option To: Arnaldo Carvalho de Melo References: <1485423339-22780-1-git-send-email-treeze.taeung@gmail.com> <1485423339-22780-2-git-send-email-treeze.taeung@gmail.com> <20170126185801.GU10340@kernel.org> Cc: linux-kernel@vger.kernel.org, Jiri Olsa , Namhyung Kim , Ingo Molnar , Peter Zijlstra , Wang Nan From: Taeung Song Message-ID: <5bd318a9-3fdf-6ece-5f74-762309838ff8@gmail.com> Date: Fri, 27 Jan 2017 12:52:13 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20170126185801.GU10340@kernel.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> Cc: Namhyung Kim >> Signed-off-by: Taeung Song >> --- >> 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