Re: [RFC/PATCH] perf report: Show random usage tip on the help line

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: "Wangnan (F)" <wangnan0@huawei.com>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Jiri Olsa <jolsa@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
	David Ahern <dsahern@gmail.com>,
	Stephane Eranian <eranian@google.com>,
	Andi Kleen <andi@firstfloor.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Subject: Re: [RFC/PATCH] perf report: Show random usage tip on the help line
Date: Tue, 5 Jan 2016 13:40:10 -0300	[thread overview]
Message-ID: <20160105164010.GE15669@kernel.org> (raw)
In-Reply-To: <20160105104307.GA13561@danjae.kornet>

Em Tue, Jan 05, 2016 at 07:43:07PM +0900, Namhyung Kim escreveu:
> Hi,
> 
> On Tue, Jan 05, 2016 at 02:32:47PM +0800, Wangnan (F) wrote:
> > 
> > 
> > On 2016/1/5 13:36, Namhyung Kim wrote:
> > >Currently perf report only shows a help message "For a higher level
> > >overview, try: perf report --sort comm,dso" unconditionally (even if
> > >the sort keys were used).  Add more help tips and show randomly.
> > >
> > >Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > >---
> > 
> > That's really funny.
> 
> Thanks for your feedback!

:-)

> > 
> > Some inconvenience:
> > 
> >  1. Tip is never change during one execution of 'perf report', even if
> >     I switch to another view using 'enter' and switch back. It should better
> >     if tips updated when redrawing.
> 
> Hmm.. I think it's a preference.  I'd go for simplicity then. :)

Yeah, that can be easily done on top, after we get some more tips in.

> >  2. I think add a "Tip: " prefix to the content should be better, or users
> > may confuse what he/her doing causes this message
> 
> OK.
> 
> > 
> >  3. What about creating a tools/perf/Documentation/tips.txt and generate
> > tips table dynamically?
> 
> I don't see much difference doing that.  I guess most of users don't
> want to go to see the documentation anyway.  Do I miss something?

Yes, I think what he suggests is to use:

  	tips = strlist__new("file://tools/perf/Documentation/tips.txt", NULL);

And then use:

	tip = strlist__entry(tips, random() % strlist__nr_entries(tips));

Or even do as 'perf trace' does, and have a directory with one file per
tip, see 005438a8eef0 ("perf trace: Support 'strace' syscall event
groups")

> Btw, does anyone have some tips to add? :)

Lets get the mechanism right and then proof read the tips you provided
:-)

- Arnaldo