linux-kernel - Re: [PATCH] perf: make perf.data more self-descriptive (v5)

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Message-ID: <CABPqkBT_dhR+kGVPRrimC=NrC0Rq5C-WyKoLGs5Ls+yRZMGwdA@mail.gmail.com>
Date:	Fri, 23 Sep 2011 16:22:06 +0200
From:	Stephane Eranian <eranian@...gle.com>
To:	David Ahern <dsahern@...il.com>
Cc:	Pekka Enberg <penberg@...helsinki.fi>,
	linux-kernel@...r.kernel.org, acme@...hat.com,
	peterz@...radead.org, mingo@...e.hu, robert.richter@....com,
	ak@...ux.intel.com
Subject: Re: [PATCH] perf: make perf.data more self-descriptive (v5)

On Fri, Sep 23, 2011 at 4:09 PM, David Ahern <dsahern@...il.com> wrote:
>
>
> On 09/23/2011 07:40 AM, Stephane Eranian wrote:
> >
> >
> > On Fri, Sep 23, 2011 at 3:36 PM, David Ahern <dsahern@...il.com
> > <mailto:dsahern@...il.com>> wrote:
> >
> >
> >
> >     On 09/23/2011 03:04 AM, Stephane Eranian wrote:
> >     > On Fri, Sep 23, 2011 at 10:03 AM, Pekka Enberg
> >     <penberg@...helsinki.fi <mailto:penberg@...helsinki.fi>> wrote:
> >     >> Hi Stephane!
> >     >>
> >     >> On Fri, Sep 23, 2011 at 10:31 AM, Stephane Eranian
> >     <eranian@...gle.com <mailto:eranian@...gle.com>> wrote:
> >     >>>> So how important is this information? The output is going to be
> >     somewhat
> >     >>>> awkward for very large CPU counts... :-)
> >     >>>>
> >     >>> It is useful to determine how CPUs share caches for instance.
> >     >>> It can get large but large, but the meta-data header is not
> >     printed by
> >     >>> default, you need to request it with the -I option.
> >     >>
> >     >> Well, sure but it blocks rest of the interesting information too.
> >     It seems to me
> >     >> that the CPU information could be truncated to some sane limit by
> >     default and
> >     >> introduce a command line option for users that really want to see
> >     all of it.
> >     >>
> >     > Ok, so here is a proposal:
> >     > - reorder the info so one liners appear first
> >     > - display the "truncated" info by default (no option)
> >     > - truncated: numa topo, cpu topo, stop after 4 cpus/nodes, print msg
> >
> >     Earlier I gave an example for a 2 socket, quad-core with hyperthreading
> >     (16 cpus total):
> >        https://lkml.org/lkml/2011/9/6/355
> >     The information is repetitive. It would be better to devise a way to
> >     reduce the repetition versus truncate the information.
> >
> >
> > I have modified the patch to NOT print the CPU, NUMA topology by
> > default (but mentioned they are available with the -I option). The
> > other bits of information are displayed systematically (no truncation).
> >
> > What ways would you propose to still print the info is a less-verbose
> > fashion?
> >
>
> for example, sibling cores:
> # CPU0 sibling cores  : 0,2,4,6,8,10,12,14
>
> you don't need to print that info for CPUs 0,2,4,6,8,10,12,14. Just
> once. Maybe just:
>
> # CPU sibling cores  : 0,2,4,6,8,10,12,14
>
> Similarly for the threads:
> # CPU sibling threads: 0,8
>
>
> That drops the output from 32 lines to 10.
>
> # CPU sibling cores  : 0,2,4,6,8,10,12,14
> # CPU sibling cores  : 1,3,5,7,9,11,13,15
> # CPU sibling threads: 0,8
> # CPU sibling threads: 1,9
> # CPU sibling threads: 2,10
> # CPU sibling threads: 3,11
> # CPU sibling threads: 4,12
> # CPU sibling threads: 5,13
> # CPU sibling threads: 6,14
> # CPU sibling threads: 7,15
>
Ok, I will look into this.
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