linux-kernel - Re: [PATCH 09/19] perf ftrace: add support for trace option tracing

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Date:   Wed, 20 May 2020 18:03:11 -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 09/19] perf ftrace: add support for trace option
 tracing_thresh

Em Sun, May 10, 2020 at 11:06:18PM +0800, Changbin Du escreveu:
> This adds an option '--tracing-thresh' to setup trace duration threshold
> for funcgraph tracer.

Ditto
 
> Signed-off-by: Changbin Du <changbin.du@...il.com>
> ---
>  tools/perf/builtin-ftrace.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index f11f2d3431b0..20bc14d6c5fb 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -43,6 +43,7 @@ struct perf_ftrace {
>  	bool			nosleep_time;
>  	bool			nofuncgraph_irqs;
>  	bool			long_info;
> +	unsigned		tracing_thresh;
>  };
>  
>  struct filter_entry {
> @@ -213,6 +214,9 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
>  	if (write_tracing_file("max_graph_depth", "0") < 0)
>  		return -1;
>  
> +	if (write_tracing_file("tracing_thresh", "0") < 0)
> +		return -1;
> +
>  	reset_tracing_filters();
>  	reset_tracing_options(ftrace);
>  	return 0;
> @@ -392,6 +396,21 @@ static int set_tracing_long_info(struct perf_ftrace *ftrace)
>  	return 0;
>  }
>  
> +static int set_tracing_thresh(struct perf_ftrace *ftrace)
> +{
> +	char buf[16];
> +
> +	if (ftrace->tracing_thresh == 0)
> +		return 0;
> +
> +	snprintf(buf, sizeof(buf), "%d", ftrace->tracing_thresh);
> +
> +	if (write_tracing_file("tracing_thresh", buf) < 0)
> +		return -1;
> +
> +	return 0;
> +}
> +
>  static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
>  {
>  	char *trace_file;
> @@ -475,6 +494,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
>  		goto out_reset;
>  	}
>  
> +	if (set_tracing_thresh(ftrace) < 0) {
> +		pr_err("failed to set tracing thresh\n");
> +		goto out_reset;
> +	}
> +
>  	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
>  		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
>  		goto out_reset;
> @@ -616,6 +640,8 @@ int cmd_ftrace(int argc, const char **argv)
>  		    "Ignore functions that happen inside interrupt (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,
> +		     "Only show functions of which the duration is greater than <n>µs"),
>  	OPT_END()
>  	};
>  
> -- 
> 2.25.1
> 

-- 

- Arnaldo