From mboxrd@z Thu Jan  1 00:00:00 1970
Content-Type: multipart/mixed; boundary="===============7401163773278878971=="
MIME-Version: 1.0
From: Ingo Molnar <mingo@kernel.org>
To: lkp@lists.01.org
Subject: Re: [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Date: Mon, 15 Aug 2016 07:03:00 +0200
Message-ID: <20160815050300.GA16267@gmail.com>
In-Reply-To: <CA+55aFxbLsD_btd0qXpuxTqAB5OQF1O+v7-OMgj8ftBE4Qd7WA@mail.gmail.com>
List-Id: <oe-lkp.lists.linux.dev>

--===============7401163773278878971==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> Make sure you actually use "perf record -e cycles:pp" or something
> that uses PEBS to get real profiles using CPU performance counters.

Btw., 'perf record -e cycles:pp' is the default now for modern versions
of perf tooling (on most x86 systems) - if you do 'perf record' it will
just use the most precise profiling mode available on that particular
CPU model.

If unsure you can check the event that was used, via:

  triton:~> perf report --stdio 2>&1 | grep '# Samples'
  # Samples: 27K of event 'cycles:pp'

Thanks,

	Ingo

--===============7401163773278878971==--


From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752377AbcHOFDH (ORCPT <rfc822;w@1wt.eu>);
	Mon, 15 Aug 2016 01:03:07 -0400
Received: from mail-wm0-f66.google.com ([74.125.82.66]:32973 "EHLO
	mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750977AbcHOFDG (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 15 Aug 2016 01:03:06 -0400
Date: Mon, 15 Aug 2016 07:03:00 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>, Tejun Heo <tj@kernel.org>,
        Wu Fengguang <fengguang.wu@intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Christoph Hellwig <hch@lst.de>, "Huang, Ying" <ying.huang@intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Bob Peterson <rpeterso@redhat.com>, LKP <lkp@01.org>,
        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression
Message-ID: <20160815050300.GA16267@gmail.com>
References: <20160811155721.GA23015@lst.de>
 <CA+55aFyVqdk0p6pmEx_gOs_AiH0TJ23ZEUDZHc9kiFbqEk8UOw@mail.gmail.com>
 <20160812005442.GN19025@dastard>
 <CA+55aFxx5sU=y1ec4NjTqH61qwKVWd4oRu1tMZovQRKENBBsmA@mail.gmail.com>
 <20160812035645.GQ19025@dastard>
 <CA+55aFwYcjXn7kpLFWQ=jF0sSrhEfZhqNsjR+6O89OOH9qRNOw@mail.gmail.com>
 <20160815004826.GW19025@dastard>
 <CA+55aFy8-biqTbDwwTqOPALAD+WN_PgDBK6HPTxTRiVgj5bA8Q@mail.gmail.com>
 <20160815022808.GX19025@dastard>
 <CA+55aFxbLsD_btd0qXpuxTqAB5OQF1O+v7-OMgj8ftBE4Qd7WA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFxbLsD_btd0qXpuxTqAB5OQF1O+v7-OMgj8ftBE4Qd7WA@mail.gmail.com>
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


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> Make sure you actually use "perf record -e cycles:pp" or something
> that uses PEBS to get real profiles using CPU performance counters.

Btw., 'perf record -e cycles:pp' is the default now for modern versions
of perf tooling (on most x86 systems) - if you do 'perf record' it will
just use the most precise profiling mode available on that particular
CPU model.

If unsure you can check the event that was used, via:

  triton:~> perf report --stdio 2>&1 | grep '# Samples'
  # Samples: 27K of event 'cycles:pp'

Thanks,

	Ingo