Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751803AbaLRXMC (ORCPT ); Thu, 18 Dec 2014 18:12:02 -0500 Received: from www.linutronix.de ([62.245.132.108]:60580 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751658AbaLRXMA (ORCPT ); Thu, 18 Dec 2014 18:12:00 -0500 Date: Fri, 19 Dec 2014 00:11:52 +0100 (CET) From: Thomas Gleixner To: Jesse Brandeburg cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] genirq: fix symbol export for __irq_set_affinity In-Reply-To: <20141218144836.0000091d@unknown> Message-ID: References: <20141218223031.23847.86103.stgit@jbrandeb-cp2.jf.intel.com> <20141218144836.0000091d@unknown> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 18 Dec 2014, Jesse Brandeburg wrote: > On Thu, 18 Dec 2014 23:42:03 +0100 > Thomas Gleixner wrote: > > > On Thu, 18 Dec 2014, Jesse Brandeburg wrote: > > > Enabling this function means that kernel drivers can include > > > an initial affinity setting for the interrupt, instead of all > > > interrupts starting out life on CPU0. It seems to have just > > > been an oversight that it was not included. > > > And why needs this to be called from modules? Just because or is there > > a legitimate reason? IOW, you forgot to describe the actual usecase. > > As stated above, the use case for my interest is making a network > driver's many interrupt vectors not all show up on CPU0. Of course a > user can work around this by manually tuning smp_affinity, but I have > seen many reports from users and testers where the performance of the > network was really bad due to all network interrupts on CPU0. > > This allows the driver to set a sane default smp_affinity value at > driver load. Fair enough. Overloaded brain missed parts of the explanation. :) > Would you instead consider a patch where if a user calls the > set_irq_affinity_hint that the initial affinity is set to the hinted > value? That would make a lot of sense, because you probably will set the affinity hint anyway, right? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/