From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757536AbaEFMmn (ORCPT ); Tue, 6 May 2014 08:42:43 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36531 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757342AbaEFMmg (ORCPT ); Tue, 6 May 2014 08:42:36 -0400 Message-ID: <1399380153.5192.219.camel@marge.simpson.net> Subject: Re: Slow down stupid pounders From: Mike Galbraith To: Borislav Petkov Cc: lkml , x86-ml , Peter Zijlstra , Mel Gorman , Steven Rostedt Date: Tue, 06 May 2014 14:42:33 +0200 In-Reply-To: <20140506102924.GA25013@pd.tnic> References: <20140506102924.GA25013@pd.tnic> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-05-06 at 12:29 +0200, Borislav Petkov wrote: > Hi, > > so I'm getting sick'n'tired of all those bug reports of people pounding > cpu hotplug with stupid scripts. > > * We know cpu hotplug is fragile/buggy/crap/needs proper rewrite. > > * Stupid hotplugging script doesn't resemble any real use case - go use > a real benchmark/stress test to trigger bugs. > > So if we can't make pounders stop jerking off, let's make it > uninterestingly slow. Stupid patch below, it might be completely idiotic > to do it this way but at least starts the discussion about this being a > really annoying issue which needs some sort of dealing with. > > I dunno, we can make it configurable (which will probably defeat its > purpose partially), we can do some more fancy ratelimiting, per cpu, > whatever... we'll see. > > Opinions, flames? Damn. I was gonna suggest we shorten hours in -rt kernels to achieve my full day stress testing survival goal. -Mike