[PATCH 02/22] perf hists browser: Fix event group display

From: Arnaldo Carvalho de Melo
Date: Tue Sep 20 2016 - 16:06:32 EST

From: Namhyung Kim <namhyung@xxxxxxxxxx>

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.

Reported-by: Milian Wolff <milian.wolff@xxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Fixes: 89fee7094323 ("perf hists: Do column alignment on the format iterator")
Link: http://lkml.kernel.org/r/20160912061958.16656-2-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
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;