Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1030530AbbKDPfQ (ORCPT <rfc822;w@1wt.eu>);
	Wed, 4 Nov 2015 10:35:16 -0500
Received: from mail-pa0-f52.google.com ([209.85.220.52]:33142 "EHLO
	mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1030417AbbKDPfM (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 4 Nov 2015 10:35:12 -0500
Date: Thu, 5 Nov 2015 00:34:57 +0900
From: Namhyung Kim <namhyung@kernel.org>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.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>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Andi Kleen <andi@firstfloor.org>, Kan Liang <kan.liang@intel.com>
Subject: Re: [PATCHSET 0/4] perf report: Support folded callchain output (v4)
Message-ID: <20151104153457.GA30495@danjae.kornet>
References: <1446555131-25495-1-git-send-email-namhyung@kernel.org>
 <20151103144053.GL21609@kernel.org>
 <CAE40pdexwH=iwb5WhwGrQuzrBg=fys1A1YgA593oYVeABaVJgQ@mail.gmail.com>
 <20151104015433.GA19283@sejong>
 <CAE40pdepmignV1MvpCkcwJFp=3Q25okqgtz=jcwnpcrBgAohFA@mail.gmail.com>
 <20151104145131.GI13236@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20151104145131.GI13236@kernel.org>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 3705
Lines: 96

Hi Arnaldo and Brendan,

On Wed, Nov 04, 2015 at 11:51:31AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Nov 03, 2015 at 10:02:32PM -0800, Brendan Gregg escreveu:
> > On Tue, Nov 3, 2015 at 5:54 PM, Namhyung Kim <namhyung@kernel.org> wrote:
> > > Ah, makes sense.  So it'd look like
> 
> > >   $ perf report --stdio -g folded,count,info -F none -s comm
> > >   $ perf report --stdio -g folded,count,info -F none -s pid
> 
> > > The output would be
> 
> > >   809 swapper-0 cpu_bringup_and_idle;cpu_startup_entry;default_idle_call;arch_cpu_idle;default_idle;xen_hypercall_sched_op
>  
> > Thanks, looks almost right: a couple of minor changes:
>  
> > 1. If perf already has the precedent of "PID:comm", instead of my
> > "comm-PID", then maybe it should use "PID:comm" for perf consistency.
> > Doesn't make much difference to me.

Right.  Actually I'd like to write it that way.. ;-)


> > 2. The second space, delimiting "PID:comm" (or comm) and the stack...
> > I'm nervous about using space as a delimiter any more than once, since
> > it can also appear in comm (eg, "java main") and frames (eg,
> > "JavaCalls::call_helper(JavaValue*, methodHandle*, JavaCallArguments*,
> > Thread*)" -- that's direct from "perf script"!). I'd consider making
> > it a semicolon:

Fair enough.


>  
> > 809 swapper-0;cpu_bringup_and_idle;cpu_startup_entry;...
>  
> > So the output is "value key", and key is a semicolon delimited stack
> > with an optional comm or PID:comm frame at the start.
> 
> Agreed, but then, we can have some sort of default and also be able to,
> using -F, specify what are the fields we want, and in which order, and I
> liked your suggestion of being able to specify "-F none" and that mean
> no hist line to be produced.
> 
> Likewise, the way that each callchain line should be formatted should be
> programmable via the command line, via the -g option, no? Then script
> writers could use it in a way that doesn't requires further processing,
> as Brendan showed.

Right.  So '-s <key1>[,<key2>,...] -g info' can control which info is
displayed along with the callchains.

  $ perf report -s comm,dso -g folded,count,info -F none
  809 swapper;[kernel.vmlinux];cpu_bringup_and_idle;cpu_startup_entry;...

Note that the info part (swapper;[kernel.vmlinux]) is also separated
by a semicolon.  But I think it's ok since it's controlled by command
line, so script can know how many entries will be.


> 
> But yeah, the value is the semicolon delimited stack all the way to the
> comm/PID:comm if there are more than one or if the user asks it to be
> there via a -g keyword, all the other counts/info are just relative to
> that, CSV or whatever other delimiter the user asks it to, and space is
> not an option, as we know it can appear in the middle of a COMM:

Yes, I think that we should use a given separator (using -t option)
instead of hard-coded semicolon.  Although it'd be rare, it seems
possible to use semicolons in the comm name too.

Thanks,
Namhyung


> 
> [root@zoo ~]# perf report -s comm | grep '[a-zA-Z] [a-zA-Z]'
> # To display the perf.data header info, please use
> # --header/--header-only options.
> # Total Lost Samples: 0
> # Samples: 164K of event 'cycles:pp'
> # Event count (approx.): 34422160859
>      0.11%  DOM Worker     
>      0.10%  JS Helper      
>      0.01%  Qt bearer threa
>      0.00%  Socket Thread  
>      0.00%  dconf worker   
>      0.00%  JS Watchdog    
> [root@zoo ~]#
> 
> - Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/