linux-kernel - Re: [PATCH 4/4] sched/numa: Do not move imbalanced load purely on the basis of an idle CPU

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180912093621.GY24106@hirez.programming.kicks-ass.net>
Date:   Wed, 12 Sep 2018 11:36:21 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:     Mel Gorman <mgorman@...hsingularity.net>,
        Ingo Molnar <mingo@...nel.org>,
        Rik van Riel <riel@...riel.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] sched/numa: Do not move imbalanced load purely on
 the basis of an idle CPU

On Wed, Sep 12, 2018 at 12:24:10PM +0530, Srikar Dronamraju wrote:

> Kernel A = 4.18+ 13 sched patches part of v4.19-rc1.
> Kernel B = Kernel A + 6 patches (http://lore.kernel.org/lkml/1533276841-16341-1-git-send-email-srikar@linux.vnet.ibm.com)
> Kernel C = Kernel B - (Avoid task migration for small numa improvement) i.e
> 	http://lore.kernel.org/lkml/1533276841-16341-4-git-send-email-srikar@linux.vnet.ibm.com
> 	+ 2 patches from Mel
> 	(Do not move imbalanced load purely)
> 	http://lore.kernel.org/lkml/20180907101139.20760-5-mgorman@techsingularity.net
> 	(Stop comparing tasks for NUMA placement)
> 	http://lore.kernel.org/lkml/20180907101139.20760-4-mgorman@techsingularity.net

But that's not a fair comparison :/ You've complicated things by adding
that second patch from Mel.

Now you cannot (unambiguously) tell what the cause for the performance
difference is.