linux-kernel - Re: [PATCH v1] perf top: Make zeroing histogram on refresh the default

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Message-ID: <CAP-5=fUzbaBCKEVxYTyzv1K3s+BcGCAjJcv-g9SrZFO+EBX3oA@mail.gmail.com>
Date: Wed, 5 Jun 2024 16:51:17 -0700
From: Ian Rogers <irogers@...gle.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	Changbin Du <changbin.du@...wei.com>, John Fastabend <john.fastabend@...il.com>, 
	Andrii Nakryiko <andrii@...nel.org>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v1] perf top: Make zeroing histogram on refresh the default

On Tue, May 21, 2024 at 12:46 PM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> On Fri, May 17, 2024 at 06:25:16PM -0700, Namhyung Kim wrote:
> > On Thu, May 16, 2024 at 3:22 PM Ian Rogers <irogers@...gle.com> wrote:
> > > Instead of decaying histograms over time change it so that they are
> > > zero-ed on each perf top refresh. Previously the option '-z', or
> > > pressing 'z' in tui mode, would enable this behavior. Decaying samples
> > > is non-intuitive as it isn't how "top" works. Make zeroing on refresh
> > > the default and rename the command line options from 'z' to 'Z' and
> > > 'zero' to 'decay'.
>
> > While it may make more sense, I'm afraid of changing the default
> > behavior.  I think we can add a config option for this.
>
> > Also instead of adding a new option, it should be able to use the
> > existing --no-zero option.
>
> Hi Ingo,
>
>         What do you think? -z and the default to decaying is in 'perf
> top' since the very beginning, when it was called kerneltop:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e0143bad9dbf2a8fad4c5430562bceba196b66ea

Ping, thanks,
Ian