Re: [PATCH v2 1/2] perf hists browser: Support horizontal scrolling with '<' and '>' key

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Aug 11, 2015 at 01:15:59AM +0200, Jiri Olsa escreveu:
> On Mon, Aug 10, 2015 at 08:14:45PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Aug 11, 2015 at 01:02:56AM +0200, Jiri Olsa escreveu:
> > > On Mon, Aug 10, 2015 at 07:58:22PM -0300, Arnaldo Carvalho de Melo wrote:
> > > > > it'd really help for perf mem output, which is quite wide.. and we probably
> > > > > have more wide outputs, or users with narrow terminals ;-)

> > > > I'm not going against horizontal scrolling, it is needed, sure thing,
> > > > its surprising we are doing this only now. What I am asking is this fine
> > > > scrolling of one column per <- or -> keypress, but I really need to try
> > > > it with things like 'perf mem', I thought that when you pressed '>', in
> > > > this patch, it would move entire sort key columns, not just one vertical
> > > > column one character wide, right?

> > > yep, the whole sort column seemed more usefull,

So, that wasn't what was implemented in Namhyung's patchkit, right? I.e.
it scrolls characters, not columns.

Can you take a look at the patchkit I put together at my tree, branch:

	tmp.perf/ui_browser.horiz_scroll

https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/log/?h=tmp.perf/ui_browser.horiz_scroll

The last two patches do it:

  $ git log --oneline | head -2
  8a7684de198b perf hists browser: Implement horizontal scrolling
  a00e506da09e perf ui browser: Optional horizontal scrolling key binding
  $

  $ git diff HEAD^^ --stat
   tools/perf/ui/browser.c        | 14 ++++++++++++++
   tools/perf/ui/browser.h        |  2 +-
   tools/perf/ui/browsers/hists.c | 22 +++++++++++++++++-----
   3 files changed, 32 insertions(+), 6 deletions(-)
  $

Several lines are just comments explaining some tricks due to me not
having found a counter for the number of colums somewhere and reusing
the first loop that traverses them all to do the counting.

There are two before those that at first I thought was needed, but ended
up not using (would have to render the whole line in ui_browser to do
the scrolling at line printing time, works only for browsers where just
one call to ui_browser__printf or ui_browser__write_nstring is done,
but I ended up leaving it there anyway, to try to make the
hist_browser.c and other ui_browser implementations (annotate, etc)
independent of libslang:

  $ git log --oneline | head -4 | tail -2
  e7534e88dfa3 perf ui browser: Introduce ui_browser__printf()
  2fe0f7e4b73e perf ui browser: Introduce ui_browser__write_nstring()
  $

Tested it with 'perf mem record -g -a' + 'perf mem report', and I liked
how it works, please check if you like it too :-)

The <- and -> keys are reused just when the horizontal scrolling mode is
activate by setting ui_browser->columns, the hists_browser (perf report,
perf top) will continue having ENTER and ESC, as always, to
select/deselect things.

If we insist we need character by character scrolling, or if we need
that move in other browser (annotate, for instance) its just a matter of
using ui_browser->horiz_scroll as a char counter and use it in the
ui_browser->refresh() calls when rendering each line.

- Arnaldo

> > > though 1 vertical column is nice also
> > 
> > We can get that by using the right and left keys while pressing shift or
> > alt, I think.
> 
> works for me
> 
> jirka