linux-kernel - Re: [PATCH 1/7] perf hists browser: Fix event group display

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Message-ID: <20160912142338.GB4897@kernel.org>
Date:   Mon, 12 Sep 2016 11:23:38 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Jiri Olsa <jolsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <andi@...stfloor.org>,
        Milian Wolff <milian.wolff@...b.com>
Subject: Re: [PATCH 1/7] perf hists browser: Fix event group display

Em Mon, Sep 12, 2016 at 03:19:52PM +0900, Namhyung Kim escreveu:
> Milian reported that the event group on TUI shows duplicated overhead.
> This was due to a bug on calculating hpp->buf position.  The
> hpp_advance() was called from __hpp__slsmg_color_printf() on TUI but
> it's already called from the hpp__call_print_fn macro in __hpp__fmt().
> The end result is that the print function returns number of bytes it
> printed but the buffer advanced twice of the length.
> 
> This is generally not a problem since it doesn't need to access the
> buffer again.  But with event group, overhead needs to be printed
> multiple times and hist_entry__snprintf_alignment() tries to fill the
> space with buffer after it printed.  So it (brokenly) showed the last
> overhead again.
> 
> The bug was there from the beginning, but I think it's only revealed
> when the alignment function was added.

Thanks, applied.

Milian, if you could, please test this, I would then change the line
below to Reported-and-Tested-by: you, if I get it before my next pull
req to Ingo.

- Arnaldo
 
> Reported-by: Milian Wolff <milian.wolff@...b.com>
> Fixes: 89fee7094323 ("perf hists: Do column alignment on the format iterator")
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/ui/browsers/hists.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index f0611c937d4b..35e44b1879e3 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -1097,7 +1097,6 @@ static int __hpp__slsmg_color_printf(struct perf_hpp *hpp, const char *fmt, ...)
>  	ret = scnprintf(hpp->buf, hpp->size, fmt, len, percent);
>  	ui_browser__printf(arg->b, "%s", hpp->buf);
>  
> -	advance_hpp(hpp, ret);
>  	return ret;
>  }
>  
> -- 
> 2.9.3