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Subject: Re: [PATCH v2] perf annotate: allow 's' on source code lines
From:   Riccardo Mancini <rickyman7@gmail.com>
To:     Ian Rogers <irogers@google.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>, Martin Liska <mliska@suse.cz>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Fri, 25 Jun 2021 17:53:35 +0200
In-Reply-To: <CAP-5=fXWFvcvNOA+wJMSCp2Qz7EVruufvFBLWEXfdezeEJGUTA@mail.gmail.com>
References: <20210624223423.189550-1-rickyman7@gmail.com>
         <CAP-5=fXWFvcvNOA+wJMSCp2Qz7EVruufvFBLWEXfdezeEJGUTA@mail.gmail.com>
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Hi Ian,
 
On Thu, 2021-06-24 at 22:37 -0700, Ian Rogers wrote:
> On Thu, Jun 24, 2021 at 3:37 PM Riccardo Mancini <rickyman7@gmail.com> wrote:
> > 
> > In perf annotate, when 's' is pressed on a line containing
> > source code, it shows the message "Only available for assembly
> > lines".
> > This patch gets rid of the error, moving the cursr to the next
> > available asm line (or the closest previous one if no asm line
> > is found moving forwards), before hiding source code lines.
> > 
> > Changes in v2:
> >  - handle case of no asm line found in
> >    annotate_browser__find_next_asm_line by returning NULL and
> >    handling error in caller.
> > 
> > Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
> 
> Acked-by: Ian Rogers <irogers@google.com>
> 
> > ---
> >  tools/perf/ui/browsers/annotate.c | 32 ++++++++++++++++++++++++++++---
> >  1 file changed, 29 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/perf/ui/browsers/annotate.c
> > b/tools/perf/ui/browsers/annotate.c
> > index ad0a70f0edaf..f5509a958e38 100644
> > --- a/tools/perf/ui/browsers/annotate.c
> > +++ b/tools/perf/ui/browsers/annotate.c
> > @@ -343,6 +343,29 @@ static void annotate_browser__calc_percent(struct
> > annotate_browser *browser,
> >         browser->curr_hot = rb_last(&browser->entries);
> >  }
> > 
> > +static struct annotation_line *annotate_browser__find_next_asm_line(
> > +                                       struct annotate_browser *browser,
> > +                                       struct annotation_line *al)
> > +{
> > +       struct annotation_line *it = al;
> > +
> > +       /* find next asm line */
> > +       list_for_each_entry_continue(it, browser->b.top, node) {
> > +               if (it->idx_asm >= 0)
> > +                       return it;
> > +       }
> > +
> > +       /* no asm line found forwards, try backwards */
> > +       it = al;
> > +       list_for_each_entry_continue_reverse(it, browser->b.top, node) {
> > +               if (it->idx_asm >= 0)
> > +                       return it;
> > +       }
> > +
> > +       /* There are no asm lines */
> > +       return NULL;
> > +}
> > +
> >  static bool annotate_browser__toggle_source(struct annotate_browser
> > *browser)
> >  {
> >         struct annotation *notes = browser__annotation(&browser->b);
> > @@ -363,9 +386,12 @@ static bool annotate_browser__toggle_source(struct
> > annotate_browser *browser)
> >                 browser->b.index = al->idx;
> >         } else {
> >                 if (al->idx_asm < 0) {
> > -                       ui_helpline__puts("Only available for assembly
> > lines.");
> > -                       browser->b.seek(&browser->b, -offset, SEEK_CUR);
> > -                       return false;
> > +                       /* move cursor to next asm line */
> 
> comment nit, perhaps prefer "closest" rather than "next" due to
> searching backward.

The backward search is just a fallback in case the forward one finds no asm
line, which I believe is unlikely. Maybe it's also impossible, but I don't
really know how those lines are generated, so I put a fallback in place.
Furthermore, "closest" would imply that a previous asm line could be chosen over
a subsequent one if closer, even if the latter is present.

Thanks,
Riccardo 

> 
> Thanks,
> Ian
> 
> > +                       al = annotate_browser__find_next_asm_line(browser,
> > al);
> > +                       if (!al) {
> > +                               browser->b.seek(&browser->b, -offset,
> > SEEK_CUR);
> > +                               return false;
> > +                       }
> >                 }
> > 
> >                 if (al->idx_asm < offset)
> > --
> > 2.31.1
> >