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 S965562AbcIVRKW (ORCPT <rfc822;w@1wt.eu>);
        Thu, 22 Sep 2016 13:10:22 -0400
Received: from mail-pa0-f54.google.com ([209.85.220.54]:36395 "EHLO
        mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S965135AbcIVRKU (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 22 Sep 2016 13:10:20 -0400
From: bsegall@google.com
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
        Ingo Molnar <mingo@kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Yuyang Du <yuyang.du@intel.com>,
        Morten Rasmussen <Morten.Rasmussen@arm.com>,
        Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Paul Turner <pjt@google.com>
Subject: Re: [PATCH 7/7 v3] sched: fix wrong utilization accounting when switching to fair class
References: <1473666472-13749-1-git-send-email-vincent.guittot@linaro.org>
        <1473666472-13749-8-git-send-email-vincent.guittot@linaro.org>
        <20160915131807.GS5008@twins.programming.kicks-ass.net>
        <CAKfTPtBy3NQGBEA1NAnZm_dqBKcEAxznNQYDLm4y+-Q_RJ_n-w@mail.gmail.com>
        <20160916121626.GN5012@twins.programming.kicks-ass.net>
        <CAKfTPtC0ixfQ7iuaDd-QH0-SGwJ8kctr1kxe_eGKjePy6hNd9g@mail.gmail.com>
        <20160920115458.GX5016@twins.programming.kicks-ass.net>
        <xm26a8f2ecdf.fsf@bsegall-linux.mtv.corp.google.com>
        <20160922083351.GV5012@twins.programming.kicks-ass.net>
Date: Thu, 22 Sep 2016 10:10:18 -0700
In-Reply-To: <20160922083351.GV5012@twins.programming.kicks-ass.net> (Peter
        Zijlstra's message of "Thu, 22 Sep 2016 10:33:51 +0200")
Message-ID: <xm261t0beu85.fsf@bsegall-linux.mtv.corp.google.com>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Peter Zijlstra <peterz@infradead.org> writes:

> On Tue, Sep 20, 2016 at 09:59:08AM -0700, bsegall@google.com wrote:
>> Peter Zijlstra <peterz@infradead.org> writes:
>> > Google has this patch-set replacing min_vruntime with an actual global
>> > 0-lag, which greatly simplifies things. If only they'd post it sometime
>> > :/ /me prods pjt and ben with a sharp stick :-)
>> >
>> 
>> No, we don't have any patches like that. I wish, we've screwed up
>> vruntime a couple of times too.
>
> Hurm, I was sure you guys were doing something entirely different from
> what mainline does.
>
> IIRC Andrew Hunter was 'working' on getting that posted. See also:
> lkml.kernel.org/r/CADroS=6Ncpao6WWXBxboB6quqUP96EnjbsDUZqNgASd_PzDGaA@mail.gmail.com

Oh, I was looking at the wrong branches. Sigh.

Yeah, we just do an unlocked "se->vruntime -= old->min_vruntime -
new->min_vruntime;" in migrate, and remove/add it in
switched_from/switched_to_fair.

This still isn't replacing min_vruntime with anything cool, perhaps you
and Andrew were using opposite definitions of relative here - we have
fair tasks always having a vruntime that is relative to min_vruntime,
rather than temporarily having the 0-based one when doing
non-SLEEP/WAKEUP.