Messages in this thread | | | Date | Fri, 25 Oct 2013 12:34:32 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf/ui/tui: don't force a refresh during progress update |
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* Patrick Palka <patrick@parcs.ath.cx> wrote:
> Each call to tui_progress__update() would forcibly refresh the entire > screen. This is somewhat inefficient and causes noticable flickering > during the startup of perf-report, especially on large/slow terminals. > > It looks like the force-refresh in tui_progress__update() serves no > purpose other than to clear the screen so that the progress bar of a > previous operation does not subsume with that of a subsequent operation. > But we can do just that in a much more efficient manner by clearing only > the region that a previous progress bar may have occupied before > repainting the new progress bar. Then the force-refresh could be > removed with no change in visuals. > > This patch disables the slow force-refresh in tui_progress__update() and > instead calls SLsmg_fill_region() on the entire area that the progress > bar may occupy before repainting it. This change makes the startup of > perf-report much faster and appear much "smoother". > > It turns out that this was a big bottleneck in the startup speed of > perf-report -- with this patch, perf-report starts up ~1.6x faster (0.8s > vs 0.5s) on my machines. (These numbers were measured by running "time > perf report" on an 8MB perf.data and pressing 'q' immediately.) > > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Ingo Molnar <mingo@redhat.com> > Signed-off-by: Patrick Palka <patrick@parcs.ath.cx> > --- > tools/perf/ui/tui/progress.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/ui/tui/progress.c b/tools/perf/ui/tui/progress.c > index 6c2184d..641049a 100644 > --- a/tools/perf/ui/tui/progress.c > +++ b/tools/perf/ui/tui/progress.c > @@ -17,13 +17,14 @@ static void tui_progress__update(u64 curr, u64 total, const char *title) > if (total == 0) > return; > > - ui__refresh_dimensions(true); > + ui__refresh_dimensions(false); > pthread_mutex_lock(&ui__lock); > y = SLtt_Screen_Rows / 2 - 2; > SLsmg_set_color(0); > SLsmg_draw_box(y, 0, 3, SLtt_Screen_Cols); > SLsmg_gotorc(y++, 1); > SLsmg_write_string((char *)title); > + SLsmg_fill_region(y, 1, 1, SLtt_Screen_Cols - 2, ' '); > SLsmg_set_color(HE_COLORSET_SELECTED); > bar = ((SLtt_Screen_Cols - 2) * curr) / total; > SLsmg_fill_region(y, 1, 1, bar, ' ');
Nice! This is something I noticed as well, never figured out the root cause of it.
Acked-by: Ingo Molnar <mingo@kernel.org>
Thanks,
Ingo
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