Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753643Ab2FTFxU (ORCPT ); Wed, 20 Jun 2012 01:53:20 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:37074 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752104Ab2FTFxS (ORCPT ); Wed, 20 Jun 2012 01:53:18 -0400 MIME-Version: 1.0 In-Reply-To: <1340149411-2972-1-git-send-email-suresh.b.siddha@intel.com> References: <1340067097.3696.6.camel@sbsiddha-desk.sc.intel.com> <1340149411-2972-1-git-send-email-suresh.b.siddha@intel.com> Date: Tue, 19 Jun 2012 22:53:18 -0700 X-Google-Sender-Auth: wB_fVX7EwVwctH8EY_phBnzS8b4 Message-ID: Subject: Re: [PATCH 1/2] x86, apic: optimize cpu traversal in __assign_irq_vector() using domain membership From: Yinghai Lu To: Suresh Siddha Cc: Alexander Gordeev , Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, gorcunov@openvz.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 26 On Tue, Jun 19, 2012 at 4:43 PM, Suresh Siddha wrote: > Currently __assign_irq_vector() goes through each cpu in the specified mask > until it finds a free vector in all the cpu's that are part of the same > interrupt domain. We visit all the interrupt domain sibling cpus to reserve > the free vector. So, when we fail to find a free vector in an interrupt > domain, it is safe to continue our search with a cpu belonging to a new > interrupt domain. No need to go through each cpu, if the domain > containing that cpu is already visited. > > Use the irq_cfg's old_domain to track the visited domains and optimize > the cpu traversal while finding a free vector in the given cpumask. > > NOTE: We can also optimize the search by using for_each_cpu and skip the > current cpu, if it is not the first cpu in the mask returned by the > vector_allocation_domain(). But re-using the cfg->old_domain to track > the visited domains will be slightly faster. > > Signed-off-by: Suresh Siddha Acked-by: Yinghai Lu -- 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/