From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from talaria.fm.intel.com (talaria.fm.intel.com [10.1.192.39]) by caduceus.fm.intel.com (8.11.6/8.11.6/d: outer.mc,v 1.51 2002/09/23 20:43:23 dmccart Exp $) with ESMTP id h0JJe3n19576 for ; Sun, 19 Jan 2003 19:40:03 GMT Received: from fmsmsxv040-1.fm.intel.com (fmsmsxvs040.fm.intel.com [132.233.42.124]) by talaria.fm.intel.com (8.11.6/8.11.6/d: inner.mc,v 1.28 2003/01/13 19:44:39 dmccart Exp $) with SMTP id h0JJlZL19192 for ; Sun, 19 Jan 2003 19:47:35 GMT content-class: urn:content-classes:message Subject: RE: 2.5.59-mm2 Date: Sun, 19 Jan 2003 11:45:35 -0800 Message-ID: <3014AAAC8E0930438FD38EBF6DCEB5647D1492@fmsmsx407.fm.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT From: "Nakajima, Jun" Sender: owner-linux-mm@kvack.org Return-Path: To: arjanv@redhat.com, Andrew Morton Cc: linux-mm@kvack.org, "Kamble, Nitin A" , "Mallick, Asit K" , "Saxena, Sunil" List-ID: We initially implemented it in user level, accessing /proc/interrupts. We have two issues/concerns at that point. And we saw better results with kernel mode. - the data structures required, such as kstat, are already in the kernel and converting the text info from /proc/interrupts was costly in user mode. - we suspect that frequent writes (asynchronous to interrupts) to /proc/irq/N/smp_affinity might expose a race condition in interrupt machinery. For example, we saw a hang caused by such a write. So to implement it in user level efficiently, we need API that - that provide binary data that can be easily processed by such a daemon, - safer API to change routing. Or we need to take a closer look at /proc/irq/N/smp_affinity. Thanks, Jun > -----Original Message----- > From: Arjan van de Ven [mailto:arjanv@redhat.com] > Sent: Saturday, January 18, 2003 12:13 PM > To: Andrew Morton > Cc: linux-mm@kvack.org; Kamble, Nitin A; Nakajima, Jun; Mallick, Asit K; > Saxena, Sunil > Subject: Re: 2.5.59-mm2 > > > > +kirq-up-fix.patch > > > > Fix the kirq build for non-SMP > > Hi, > > Is there any reason to put this complexity in the kernel instead of > doing it from a userspace daemon? > > A userspace daemon can do higher level evaluations, read config files > about the system (like numa configuration etc etc) and all 2.4/2.5 > kernels already have a userspace api for setting irq affinity.. > > an example of a simple version of such daemon is: > http://people.redhat.com/arjanv/irqbalance/irqbalance-0.03.tar.gz > > any chance of testing this in an intel lab? > > Greetings, > Arjan van de Ven -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/