From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: Resend: 3.10.32-rt31: problem with "rcu: Eliminate softirq processing from rcutree" Date: Tue, 18 Mar 2014 12:05:31 +0100 Message-ID: <20140318110531.GC10448@linutronix.de> References: <20140307162145.GC18441@linutronix.de> <20140307170419.GI3334@linux.vnet.ibm.com> <20140308200400.GA3334@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Helmut Buchsbaum , linux-rt-users@vger.kernel.org, rostedt@goodmis.org, tglx@linutronix.de To: "Paul E. McKenney" Return-path: Received: from www.linutronix.de ([62.245.132.108]:52804 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752078AbaCRLFc (ORCPT ); Tue, 18 Mar 2014 07:05:32 -0400 Content-Disposition: inline In-Reply-To: <20140308200400.GA3334@linux.vnet.ibm.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: * Paul E. McKenney | 2014-03-08 12:04:00 [-0800]: >On Sat, Mar 08, 2014 at 08:08:35PM +0100, Helmut Buchsbaum wrote: >> This is the correct point to tweak the system, I was not yet aware of! >> Thanks a lot for the hint. I just enabled RCU_BOOST with its default >> settings and the system runs smooth and stable again even in heavy >> load situations. Maybe the default for RCU_BOOST should be set to Y on >> systems using PREEMPT_RT_FULL ? > >I must defer to Sebastian on this, but seems like a good approach. Hmm. There are a few ways to break an RT system. Afaik RCU_BOOST was recommended even before this change. Steven, tglx any opinion on that? Another thing we could do is to register_shrinker() which is called before OOM. But then boosting is simple enough. > Thanx, Paul Sebastian