From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=eGSO=AR=vger.kernel.org=linux-kernel-owner@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
X-Spam-Level: 
X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no
	autolearn_force=no version=3.4.0
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	by smtp.lore.kernel.org (Postfix) with ESMTP id 3693AC433DF
	for <linux-kernel@archiver.kernel.org>; Mon,  6 Jul 2020 10:41:18 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id 0C6F62070B
	for <linux-kernel@archiver.kernel.org>; Mon,  6 Jul 2020 10:41:18 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1728933AbgGFKlR (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Mon, 6 Jul 2020 06:41:17 -0400
Received: from foss.arm.com ([217.140.110.172]:56264 "EHLO foss.arm.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1728525AbgGFKlQ (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 6 Jul 2020 06:41:16 -0400
Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14])
        by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 165A830E;
        Mon,  6 Jul 2020 03:41:16 -0700 (PDT)
Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21])
        by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6B69F3F68F;
        Mon,  6 Jul 2020 03:41:14 -0700 (PDT)
Date:   Mon, 6 Jul 2020 11:41:12 +0100
From:   Qais Yousef <qais.yousef@arm.com>
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Patrick Bellasi <patrick.bellasi@matbug.net>,
        Chris Redpath <chris.redpath@arm.com>,
        Lukasz Luba <lukasz.luba@arm.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 0/2] sched: Optionally skip uclamp logic in fast path
Message-ID: <20200706104111.yfopcjm3kiqlxhx2@e107158-lin.cambridge.arm.com>
References: <20200630112123.12076-1-qais.yousef@arm.com>
 <CAKfTPtCjTCBbGN0gN_=7MJdiY3N-PPy0ApZWH5xd7KDQ9=0yMg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <CAKfTPtCjTCBbGN0gN_=7MJdiY3N-PPy0ApZWH5xd7KDQ9=0yMg@mail.gmail.com>
User-Agent: NeoMutt/20171215
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 07/03/20 14:09, Vincent Guittot wrote:
> I have run the perf bench sched pipe that have have already run
> previously with this v6 and the results are similar to my previous
> tests:
> The impact is -1.61% similarly to v2 which is better compared the
> original -3.66% without your patch

Thanks Vincent.

Can you afford doing a capture of `perf record` and share the resulting
perf.dat with vmlinux (with debug symbols)?

Having a before/after capture would be even better.

Not sure if we can do  much about this -1.61% in your case, but it'd be good to
understand why if possible. perf bench sched pipe is very sensitive to tiniest
of changes which could be due to binary-to-binary differences.

Thanks

--
Qais Yousef