linux-kernel - Re: [PATCH 1/3] perf sort: Keep output fields in the same level

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Message-ID: <Z-H4U64qe17b4jrq@google.com>
Date: Mon, 24 Mar 2025 17:26:59 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Kan Liang <kan.liang@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org,
	Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [PATCH 1/3] perf sort: Keep output fields in the same level

On Mon, Mar 24, 2025 at 08:28:31AM +0100, Ingo Molnar wrote:
> 
> * Namhyung Kim <namhyung@...nel.org> wrote:
> 
> > > 3)
> > > 
> > > It would also be nice to be able to Ctrl-C out of a 'perf top' instance 
> > > that freezes the output or so. Or prints a snapshot in ASCII. Anything 
> > > but what it does currently: it just exits and clears the xterm screen 
> > > of all useful information...
> > > 
> > > I have to use 'f' (how many people know about that feature?) and copy & 
> > > paste anything interesting from the screen the hard way.
> > 
> > Actually I was not aware of 'f' key. :)  I think you can use 'P' to save
> > the current screen to a file.
> 
> And I was not aware of the 'P' key. :-)
> 
> Would be nice if it also printed column and meta information, i.e. if 
> it included these lines:
> 
>   Samples: 1M of event 'cycles:P', 4000 Hz, Event count (approx.): 758731362801 lost: 0/0 drop: 0/0
>   Overhead  Shared Object            Symbol
> 
> or so?

Yep, maybe we can do the same as the stdio output.

  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 7  of event 'cycles'
  # Event count (approx.): 3641468
  #
  # Overhead  Command  Shared Object     Symbol                            
  # ........  .......  ................  ..................................
  #

> 
> BTW., the approximate 'event count' is a pretty uninformative value 
> these days, right? Might as well not clutter the screen with it.

Maybe.  I don't look at the number so far but also don't feel the need
for removal.

Thanks,
Namhyung