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[PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option

Started byTaeung Song <treeze.taeung@gmail.com>
First post2017-01-31 12:40 +0100
Last post2017-02-01 15:50 +0100
Articles 5 — 3 participants

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  [PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option Taeung Song <treeze.taeung@gmail.com> - 2017-01-31 12:40 +0100
    Re: [PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-01-31 14:20 +0100
      Re: [PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option Arnaldo Carvalho de Melo <acme@kernel.org> - 2017-01-31 14:20 +0100
        Re: [PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option Taeung Song <treeze.taeung@gmail.com> - 2017-02-01 08:30 +0100
    [tip:perf/core] perf ftrace: Add ftrace.tracer config option tip-bot for Taeung Song <tipbot@zytor.com> - 2017-02-01 15:50 +0100

#1570620 — [PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option

FromTaeung Song <treeze.taeung@gmail.com>
Date2017-01-31 12:40 +0100
Subject[PATCH v2 2/4] perf ftrace: Add ftrace.tracer config option
Message-ID<t5EX0-8E-1@gated-at.bofh.it>
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

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 | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 414444d..00e228f 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 +199,26 @@ 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 {
+			pr_err("Please select function_graph(default)"
+			       "or function to use tracer.\n");
+			return -1;
+		}
+		return 0;
+	}
+
+	return 0;
+}
+
 int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int ret;
@@ -218,6 +239,10 @@ int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
 	OPT_END()
 	};
 
+	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);
 	if (!argc)
-- 
2.7.4

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#1570724

FromArnaldo Carvalho de Melo <acme@kernel.org>
Date2017-01-31 14:20 +0100
Message-ID<t5GvN-19j-41@gated-at.bofh.it>
In reply to#1570620
Em Tue, Jan 31, 2017 at 08:38:29PM +0900, Taeung Song escreveu:
> Currently perf ftrace command will select 'function_graph' or 'function'.
> So add ftrace.tracer config option to select tracer

The above is confusing, I changed it to:

    Currently 'perf ftrace' command allows selecting 'function_graph' or
    'function', defaulting to 'function_graph'.
    
    Add the ftrace.tracer config option to select the default 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
> 
> 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 | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index 414444d..00e228f 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 +199,26 @@ 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 {
> +			pr_err("Please select function_graph(default)"
> +			       "or function to use tracer.\n");
> +			return -1;
> +		}

If you use {} in the else case, use it in the other branch, also I
simplified it to be:

+	if (!strcmp(var, "ftrace.tracer")) {
+		if (!strcmp(value, "function_graph") ||
+		    !strcmp(value, "function"))
+			ftrace->tracer = value;
+		else {
+			pr_err("Please select function_graph(default)"
+			       "or function to use tracer.\n");
+			return -1;
+		}

As we know item->value will not go away (its a perf_config_item,
allocated and kept in that perf_config_set structure).

Also it doesn't make sense comparing against "function_graph" to set it
to DEFAULT_TRACER, as if we decide to change the DEFAULT_TRACER this
simply breaks.

Also you forgot to test by setting an invalid tracer, I did and noticed
that you forgot to add a space between "(default)" and "or ", please be
more careful with testing.

Also you are silently ignoring any unknown variable in this section, so
if someone has this:

cat ~/.perfconfig

[ftrace]

	trace = function


I.e. forgets the 'r', it will keep using the current default,
"function_graph" till the user checks the config and adds that missing
'r'...

I haven't changed this because I think this is so common that we should
instead have a different error return for those config callbacks that
will tell perf_config() to say something like:

  "unknown variable %s.%s\n", section_name, variable_name

- Arnaldo


> +		return 0;
> +	}
> +
> +	return 0;
> +}
> +
>  int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
>  {
>  	int ret;
> @@ -218,6 +239,10 @@ int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
>  	OPT_END()
>  	};
>  
> +	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);
>  	if (!argc)
> -- 
> 2.7.4

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#1570731

FromArnaldo Carvalho de Melo <acme@kernel.org>
Date2017-01-31 14:20 +0100
Message-ID<t5GvO-19j-57@gated-at.bofh.it>
In reply to#1570724
Em Tue, Jan 31, 2017 at 09:46:28AM -0300, Arnaldo Carvalho de Melo escreveu:
> Also you are silently ignoring any unknown variable in this section, so
> if someone has this:
> 
> cat ~/.perfconfig
> 
> [ftrace]
> 
> 	trace = function
> 
> 
> I.e. forgets the 'r', it will keep using the current default,
> "function_graph" till the user checks the config and adds that missing
> 'r'...
> 
> I haven't changed this because I think this is so common that we should
> instead have a different error return for those config callbacks that
> will tell perf_config() to say something like:
> 
>   "unknown variable %s.%s\n", section_name, variable_name

So I read a bit more the config code and ended up with this:

static int perf_ftrace_config(const char *var, const char *value, void *cb)
{
        struct perf_ftrace *ftrace = cb;

        if (prefixcmp(var, "ftrace."))
                return 0;

        if (strcmp(var, "ftrace.tracer"))
                return -1;

        if (!strcmp(value, "function_graph") ||
            !strcmp(value, "function")) {
                ftrace->tracer = value;
                return 0;
        }

	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
        return -1;
}

I.e. it will ignore variables for other sections and will stop at an unknown
variable or value for ftrace.tracer:

[root@jouet ~]# cat ~/.perfconfig 
[ftrace]
	trace = function
[root@jouet ~]# perf ftrace usleep 1
Error: wrong config key-value pair ftrace.trace=function
[root@jouet ~]# cat ~/.perfconfig 
[ftrace]
	tracer = functin
[root@jouet ~]# perf ftrace usleep 1
Please select "function_graph" (default) or "function"
Error: wrong config key-value pair ftrace.tracer=functin
[root@jouet ~]# cat ~/.perfconfig 
[ftrace]
	tracer = function
[root@jouet ~]# perf ftrace usleep 1 | head -5
          <idle>-0     [000] d...  3855.820847: switch_mm_irqs_off <-__schedule
           <...>-18550 [000] d...  3855.820849: finish_task_switch <-__schedule
           <...>-18550 [000] d...  3855.820851: smp_irq_work_interrupt <-irq_work_interrupt
           <...>-18550 [000] d...  3855.820851: irq_enter <-smp_irq_work_interrupt
           <...>-18550 [000] d...  3855.820851: rcu_irq_enter <-irq_enter
[root@jouet ~]#

- Arnaldo

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#1571290

FromTaeung Song <treeze.taeung@gmail.com>
Date2017-02-01 08:30 +0100
Message-ID<t5XwB-2To-3@gated-at.bofh.it>
In reply to#1570731

On 01/31/2017 10:15 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 31, 2017 at 09:46:28AM -0300, Arnaldo Carvalho de Melo escreveu:
>> Also you are silently ignoring any unknown variable in this section, so
>> if someone has this:
>>
>> cat ~/.perfconfig
>>
>> [ftrace]
>>
>> 	trace = function
>>
>>
>> I.e. forgets the 'r', it will keep using the current default,
>> "function_graph" till the user checks the config and adds that missing
>> 'r'...
>>
>> I haven't changed this because I think this is so common that we should
>> instead have a different error return for those config callbacks that
>> will tell perf_config() to say something like:
>>
>>   "unknown variable %s.%s\n", section_name, variable_name
>
> So I read a bit more the config code and ended up with this:
>
> static int perf_ftrace_config(const char *var, const char *value, void *cb)
> {
>         struct perf_ftrace *ftrace = cb;
>
>         if (prefixcmp(var, "ftrace."))
>                 return 0;
>
>         if (strcmp(var, "ftrace.tracer"))
>                 return -1;
>
>         if (!strcmp(value, "function_graph") ||
>             !strcmp(value, "function")) {
>                 ftrace->tracer = value;
>                 return 0;
>         }
>
> 	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
>         return -1;
> }
>
> I.e. it will ignore variables for other sections and will stop at an unknown
> variable or value for ftrace.tracer:
>
> [root@jouet ~]# cat ~/.perfconfig
> [ftrace]
> 	trace = function
> [root@jouet ~]# perf ftrace usleep 1
> Error: wrong config key-value pair ftrace.trace=function
> [root@jouet ~]# cat ~/.perfconfig
> [ftrace]
> 	tracer = functin
> [root@jouet ~]# perf ftrace usleep 1
> Please select "function_graph" (default) or "function"
> Error: wrong config key-value pair ftrace.tracer=functin
> [root@jouet ~]# cat ~/.perfconfig
> [ftrace]
> 	tracer = function
> [root@jouet ~]# perf ftrace usleep 1 | head -5
>           <idle>-0     [000] d...  3855.820847: switch_mm_irqs_off <-__schedule
>            <...>-18550 [000] d...  3855.820849: finish_task_switch <-__schedule
>            <...>-18550 [000] d...  3855.820851: smp_irq_work_interrupt <-irq_work_interrupt
>            <...>-18550 [000] d...  3855.820851: irq_enter <-smp_irq_work_interrupt
>            <...>-18550 [000] d...  3855.820851: rcu_irq_enter <-irq_enter
> [root@jouet ~]#
>

This is great!! I agonized about error message for
each other cases as above! But I think this is more precise than my patch!

Thanks,
Taeung

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#1571615 — [tip:perf/core] perf ftrace: Add ftrace.tracer config option

Fromtip-bot for Taeung Song <tipbot@zytor.com>
Date2017-02-01 15:50 +0100
Subject[tip:perf/core] perf ftrace: Add ftrace.tracer config option
Message-ID<t64oq-7aO-19@gated-at.bofh.it>
In reply to#1570620
Commit-ID:  b05d1093987a78695766b71a2d723aa65b5c25c5
Gitweb:     http://git.kernel.org/tip/b05d1093987a78695766b71a2d723aa65b5c25c5
Author:     Taeung Song <treeze.taeung@gmail.com>
AuthorDate: Tue, 31 Jan 2017 20:38:29 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 31 Jan 2017 16:20:09 -0300

perf ftrace: Add ftrace.tracer config option

Currently 'perf ftrace' command allows selecting 'function_graph' or
'function', defaulting to 'function_graph'.

Add ftrace.tracer config option to select the default 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

Committer notes:

Retesting it with invalid variables, invalid values for ftrace.tracer,
and a valid one:

  # cat ~/.perfconfig
  [ftrace]
        trace = function
  # perf ftrace usleep 1
  Error: wrong config key-value pair ftrace.trace=function
  # cat ~/.perfconfig
  [ftrace]
        tracer = functin
  # perf ftrace usleep 1
  Please select "function_graph" (default) or "function"
  Error: wrong config key-value pair ftrace.tracer=functin
  # cat ~/.perfconfig
  [ftrace]
        tracer = function
  # perf ftrace usleep 1 | head -5
          <idle>-0     [000] d...  3855.820847: switch_mm_irqs_off <-__schedule
           <...>-18550 [000] d...  3855.820849: finish_task_switch <-__schedule
           <...>-18550 [000] d...  3855.820851: smp_irq_work_interrupt <-irq_work_interrupt
           <...>-18550 [000] d...  3855.820851: irq_enter <-smp_irq_work_interrupt
           <...>-18550 [000] d...  3855.820851: rcu_irq_enter <-irq_enter
  #

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1485862711-20216-3-git-send-email-treeze.taeung@gmail.com
[ Added missign space in error message, changed the logic to make it more compact and less error prone ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-ftrace.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 414444d..c3e6436 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 +199,26 @@ out:
 	return done ? 0 : -1;
 }
 
+static int perf_ftrace_config(const char *var, const char *value, void *cb)
+{
+	struct perf_ftrace *ftrace = cb;
+
+	if (prefixcmp(var, "ftrace."))
+		return 0;
+
+	if (strcmp(var, "ftrace.tracer"))
+		return -1;
+
+	if (!strcmp(value, "function_graph") ||
+	    !strcmp(value, "function")) {
+		ftrace->tracer = value;
+		return 0;
+	}
+
+	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
+	return -1;
+}
+
 int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int ret;
@@ -218,6 +239,10 @@ int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
 	OPT_END()
 	};
 
+	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);
 	if (!argc)

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