Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758958Ab2FFWVt (ORCPT ); Wed, 6 Jun 2012 18:21:49 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:62488 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754486Ab2FFWVr convert rfc822-to-8bit (ORCPT ); Wed, 6 Jun 2012 18:21:47 -0400 MIME-Version: 1.0 In-Reply-To: References: <1337644682-19854-2-git-send-email-suresh.b.siddha@intel.com> Date: Wed, 6 Jun 2012 15:21:47 -0700 X-Google-Sender-Auth: PZ7drVZ0eeqii1AUpgOEiV4Brz4 Message-ID: Subject: Re: [tip:x86/apic] x86/x2apic/cluster: Use all the members of one cluster specified in the smp_affinity mask for the interrupt destination From: Yinghai Lu To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, suresh.b.siddha@intel.com, tglx@linutronix.de Cc: linux-tip-commits@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1960 Lines: 44 On Wed, Jun 6, 2012 at 8:04 AM, tip-bot for Suresh Siddha wrote: > Commit-ID: ?0b8255e660a0c229ebfe8f9fde12a8d4d34c50e0 > Gitweb: ? ? http://git.kernel.org/tip/0b8255e660a0c229ebfe8f9fde12a8d4d34c50e0 > Author: ? ? Suresh Siddha > AuthorDate: Mon, 21 May 2012 16:58:02 -0700 > Committer: ?Ingo Molnar > CommitDate: Wed, 6 Jun 2012 09:51:22 +0200 > > x86/x2apic/cluster: Use all the members of one cluster specified in the smp_affinity mask for the interrupt destination > > If the HW implements round-robin interrupt delivery, this > enables multiple cpu's (which are part of the user specified > interrupt smp_affinity mask and belong to the same x2apic > cluster) to service the interrupt. > > Also if the platform supports Power Aware Interrupt Routing, > then this enables the interrupt to be routed to an idle cpu or a > busy cpu depending on the perf/power bias tunable. > > We are now grouping all the cpu's in a cluster to one vector > domain. So that will limit the total number of interrupt sources > handled by Linux. Previously we support "cpu-count * > available-vectors-per-cpu" interrupt sources but this will now > reduce to "cpu-count/16 * available-vectors-per-cpu". with this patch, will waste/hide several irq vector on some cpus. for example: very beginning after boot, one irq will have vector from 16 cpus of same cluster. later if user using irq affinity change to one cpu only. cfg->domain will be not changed, but ioapic or irte will be confined to one cpu. because mask is used for new dest_id. *dest_id = apic->cpu_mask_to_apicid_and(mask, cfg->domain); all other 15 cpu vector are wasted or hided. Yinghai -- 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/