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 S1752584AbdGYPPH (ORCPT <rfc822;w@1wt.eu>);
        Tue, 25 Jul 2017 11:15:07 -0400
Received: from mx2.suse.de ([195.135.220.15]:38674 "EHLO mx1.suse.de"
        rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
        id S1752304AbdGYPPE (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 25 Jul 2017 11:15:04 -0400
Date: Tue, 25 Jul 2017 17:15:01 +0200
From: Michal Hocko <mhocko@kernel.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Oleg Nesterov <oleg@redhat.com>, Hugh Dickins <hughd@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm, oom: allow oom reaper to race with exit_mmap
Message-ID: <20170725151500.GL26723@dhcp22.suse.cz>
References: <20170724072332.31903-1-mhocko@kernel.org>
 <20170724140008.sd2n6af6izjyjtda@node.shutemov.name>
 <20170724141526.GM25221@dhcp22.suse.cz>
 <20170724145142.i5xqpie3joyxbnck@node.shutemov.name>
 <20170724161146.GQ25221@dhcp22.suse.cz>
 <20170725141723.ivukwhddk2voyhuc@node.shutemov.name>
 <20170725142617.GI26723@dhcp22.suse.cz>
 <20170725150719.74j7fbfzagrn7olb@node.shutemov.name>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20170725150719.74j7fbfzagrn7olb@node.shutemov.name>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue 25-07-17 18:07:19, Kirill A. Shutemov wrote:
> On Tue, Jul 25, 2017 at 04:26:17PM +0200, Michal Hocko wrote:
[...]
> > Thanks for retesting Kirill. Are those numbers stable over runs? E.g.
> > the run without the patch has ~3% variance while the one with the patch
> > has it smaller. This sounds suspicious to me. There shouldn't be any
> > lock contention (except for the oom killer) so the lock shouldn't make
> > any difference wrt. variability.
> 
> There's run-to-tun variability. I'll post new numbers for your new test.

That's what I've seen and the variance was quite large. I suspected
shell but if you look at the more dedicated test, the std over avg is
still quite large.
-- 
Michal Hocko
SUSE Labs