From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754505AbYIYPyH (ORCPT ); Thu, 25 Sep 2008 11:54:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752833AbYIYPxz (ORCPT ); Thu, 25 Sep 2008 11:53:55 -0400 Received: from colo.lackof.org ([198.49.126.79]:40682 "EHLO colo.lackof.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752829AbYIYPxy (ORCPT ); Thu, 25 Sep 2008 11:53:54 -0400 Date: Thu, 25 Sep 2008 09:53:43 -0600 From: Grant Grundler To: David Miller Cc: grundler@parisc-linux.org, jbarnes@virtuousgeek.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Notes from LPC PCI/MSI BoF session Message-ID: <20080925155343.GC2997@colo.lackof.org> References: <200809221229.18501.jbarnes@virtuousgeek.org> <20080924055116.GA3101@colo.lackof.org> <20080923.234705.261909334.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080923.234705.261909334.davem@davemloft.net> X-Home-Page: http://www.parisc-linux.org/ User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 23, 2008 at 11:47:05PM -0700, David Miller wrote: > From: Grant Grundler > Date: Tue, 23 Sep 2008 23:51:16 -0600 > > > Dave Miller (and others) have clearly stated they don't want to see > > CPU affinity handled in the device drivers and want irqbalanced > > to handle interrupt distribution. The problem with this is irqbalanced > > needs to know how each device driver is binding multiple MSI to it's queues. > > Some devices could prefer several MSI go to the same processor and > > others want each MSI bound to a different "node" (NUMA). > > > > Without any additional API, this means the device driver has to > > update irqbalanced for each device it supports. We thought pci_ids.h > > was a PITA...that would be trivial compared to maintaining this. > > We just need a consistent naming scheme for the IRQs to disseminate > this information to irqbalanced, then there is one change to irqbalanced > rather than one for each and every driver as you seem to suggest. That's sort of what I proposed at the end of my email: | A second solution I thought of later might be for the device driver to | export (sysfs?) to irqbalanced which MSIs the driver instance owns and | how many "domains" those MSIs can serve. irqbalanced can then write | back into the same (sysfs?) the mapping of MSI to domains and update | the smp_affinity mask for each of those MSI. > Anything that's complicated and takes more than a paragraph or two > to describe is not what we want. I agree. The discussion will need more though. thanks, grant > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html