Re: [PATCH 12/14] perf ftrace: Use pager for displaying result

[Jiri Olsa <jolsa@redhat.com>]

On Tue, Apr 23, 2013 at 05:31:10PM +0900, Namhyung Kim wrote:
> From: Namhyung Kim <namhyung.kim@lge.com>
> 
> It's convenient to use pager when seeing many lines of result.
> 
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/builtin-ftrace.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index 97293cee5597..f4efa1475cf9 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -188,6 +188,7 @@ static int do_ftrace_live(struct perf_ftrace *ftrace)
>  	signal(SIGINT, sig_handler);
>  	signal(SIGUSR1, sig_handler);
>  	signal(SIGCHLD, sig_handler);
> +	signal(SIGPIPE, sig_handler);
>  
>  	if (setup_tracing_files(ftrace) < 0)
>  		goto out_reset;
> @@ -1461,6 +1462,8 @@ __cmd_ftrace_live(struct perf_ftrace *ftrace, int argc, const char **argv)
>  						  argv, false, true) < 0)
>  		goto out_maps;
>  
> +	setup_pager();
> +
>  	ret = do_ftrace_live(ftrace);
>  
>  out_maps:
> @@ -1582,6 +1585,8 @@ __cmd_ftrace_show(struct perf_ftrace *ftrace, int argc, const char **argv)
>  	if (ftrace->dirname == NULL)
>  		ftrace->dirname = DEFAULT_DIRNAME;
>  
> +	setup_pager();
> +
>  	ret = do_ftrace_show(ftrace);
>  
>  	perf_evlist__delete_maps(ftrace->evlist);
> @@ -1643,6 +1648,7 @@ __cmd_ftrace_report(struct perf_ftrace *ftrace, int argc, const char **argv)
>  	perf_hpp__column_enable(PERF_HPP__OVERHEAD);
>  	perf_hpp__init();
>  
> +	setup_pager();
>  	setup_sorting();
>  
>  	symbol_conf.exclude_other = false;
> -- 
> 1.7.11.7
> 

for some reason I'm able to get any output for 'live' command only
when using --no-pager option. I dont get any data for:

  # ./perf ftrace live ls

  not even ls output

But sometime I dont even get ftrace output for:

  # ./perf --no-pager ftrace live ls

  just ls output


I wonder there's some race with reading trace_pipe file,
I haven't checked deeply yet..

jirka