linux-kernel - Re: [PATCH 18/19] perf ftrace: add option --latency-format to display more info about delay

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Message-ID: <20200520211423.GB3898@kernel.org>
Date:   Wed, 20 May 2020 18:14:23 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Changbin Du <changbin.du@...il.com>
Cc:     Jiri Olsa <jolsa@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 18/19] perf ftrace: add option --latency-format to
 display more info about delay

Em Sun, May 10, 2020 at 11:06:27PM +0800, Changbin Du escreveu:
> This is for the function graph tracer to display more info about latency.
> The execution context is shown in this case.

Ok, another --function-graph-opts entry, maybe you can just make -G
receive optional args.

- Arnaldo
 
> $ sudo perf ftrace -G --latency-format
> \# tracer: function_graph
> \#
>  1)  .... |   0.992 us    |  mutex_unlock();
>  1)  .... |   1.404 us    |  __fsnotify_parent();
>  1)  .... |   1.023 us    |  fsnotify();
>  1)  .... |   0.335 us    |  __sb_end_write();
>  1)  d... |   0.439 us    |  fpregs_assert_state_consistent();
>  1)  d... |               |  do_syscall_64() {
>  1)  .... |               |    __x64_sys_close() {
> 
> Signed-off-by: Changbin Du <changbin.du@...il.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 d376b37c53fc..fd8e2f305136 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -44,6 +44,7 @@ struct perf_ftrace {
>  	bool			nosleep_time;
>  	bool			nofuncgraph_irqs;
>  	bool			funcgraph_tail;
> +	bool			latency_format;
>  	bool			long_info;
>  	unsigned		tracing_thresh;
>  	bool			trace_children;
> @@ -217,6 +218,7 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
>  	write_tracing_option_file("sleep-time", "1");
>  	write_tracing_option_file("funcgraph-irqs", "1");
>  	write_tracing_option_file("funcgraph-tail", "0");
> +	write_tracing_option_file("latency-format", "0");
>  	write_tracing_option_file("funcgraph-proc", "0");
>  	write_tracing_option_file("funcgraph-abstime", "0");
>  	write_tracing_option_file("irq-info", "0");
> @@ -456,6 +458,17 @@ static int set_tracing_funcgraph_tail(struct perf_ftrace *ftrace)
>  	return 0;
>  }
>  
> +static int set_tracing_latency_format(struct perf_ftrace *ftrace)
> +{
> +	if (!ftrace->latency_format)
> +		return 0;
> +
> +	if (write_tracing_option_file("latency-format", "1") < 0)
> +		return -1;
> +
> +	return 0;
> +}
> +
>  static int set_tracing_trace_children(struct perf_ftrace *ftrace)
>  {
>  	if (!ftrace->trace_children)
> @@ -579,6 +592,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
>  		goto out_reset;
>  	}
>  
> +	if (set_tracing_latency_format(ftrace) < 0) {
> +		pr_err("failed to set tracing option latency-format\n");
> +		goto out_reset;
> +	}
> +
>  	if (set_tracing_trace_children(ftrace) < 0) {
>  		pr_err("failed to set tracing option function-fork\n");
>  		goto out_reset;
> @@ -748,6 +766,8 @@ int cmd_ftrace(int argc, const char **argv)
>  		    "Ignore functions that happen inside interrupt (function_graph only)"),
>  	OPT_BOOLEAN(0, "funcgraph-tail", &ftrace.funcgraph_tail,
>  		    "Show function tails comment (function_graph only)"),
> +	OPT_BOOLEAN(0, "latency-format", &ftrace.latency_format,
> +		    "displays additional information about the latency (function_graph only)"),
>  	OPT_BOOLEAN('l', "long-info", &ftrace.long_info,
>  		    "Show process names, PIDs, timestamps, irq-info if available"),
>  	OPT_UINTEGER(0, "tracing-thresh", &ftrace.tracing_thresh,
> -- 
> 2.25.1
> 

-- 

- Arnaldo