From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261207AbVFJUWr (ORCPT ); Fri, 10 Jun 2005 16:22:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261208AbVFJUWr (ORCPT ); Fri, 10 Jun 2005 16:22:47 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:65275 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S261207AbVFJUWp (ORCPT ); Fri, 10 Jun 2005 16:22:45 -0400 Subject: Re: Attempted summary of "RT patch acceptance" thread From: Daniel Walker Reply-To: dwalker@mvista.com To: Andrea Arcangeli Cc: "Paul E. McKenney" , Lee Revell , Tim Bird , linux-kernel@vger.kernel.org, bhuey@lnxw.com, tglx@linutronix.de, karim@opersys.com, mingo@elte.hu, pmarques@grupopie.com, bruce@andrew.cmu.edu, nickpiggin@yahoo.com.au, ak@muc.de, sdietrich@mvista.com, hch@infradead.org, akpm@osdl.org In-Reply-To: <20050610173728.GA6564@g5.random> References: <20050608022646.GA3158@us.ibm.com> <42A8D1F3.8070408@am.sony.com> <20050609235026.GE1297@us.ibm.com> <1118372388.32270.6.camel@mindpipe> <20050610154745.GA1300@us.ibm.com> <20050610173728.GA6564@g5.random> Content-Type: text/plain Organization: MontaVista Date: Fri, 10 Jun 2005 13:22:37 -0700 Message-Id: <1118434957.27756.5.camel@dhcp153.mvista.com> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-3) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2005-06-10 at 19:37 +0200, Andrea Arcangeli wrote: > > preempt-RT _can_ do something about it but only _if_ people hacks the > drivers properly and makes sure to call local_irq_save_nort instead of > local_irq_save and other explicit changes like that, things that if > missing are noticeable only during measurements with preempt-RT config > option enabled (hence the metal-hard classification of preempt-RT and > not ruby-hard definition). This is no longer an issue. We did an interrupt disable conversion so now there is only a few places that actually disable interrupts. It hasn't been tested fully, but you should be able to used whatever drivers you want and still get the same interrupt latency. However, preempt latency is still and issue for these drivers. Daniel