Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754798AbbKYOiI (ORCPT ); Wed, 25 Nov 2015 09:38:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42689 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751939AbbKYOiG (ORCPT ); Wed, 25 Nov 2015 09:38:06 -0500 Subject: Re: [PATCH] KVM: x86: Add lowest-priority support for vt-d posted-interrupts To: =?UTF-8?Q?Radim_Krcm=c3=a1r?= , "Wu, Feng" References: <1447037208-75615-1-git-send-email-feng.wu@intel.com> <20151116190314.GA12245@potion.brq.redhat.com> <20151124143154.GB13925@potion.brq.redhat.com> <20151125141238.GC13925@potion.brq.redhat.com> Cc: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" From: Paolo Bonzini Message-ID: <5655C7C9.1010008@redhat.com> Date: Wed, 25 Nov 2015 15:38:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151125141238.GC13925@potion.brq.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 851 Lines: 20 On 25/11/2015 15:12, Radim Krcmár wrote: > I think it's ok to pick any algorithm we like. It's unlikely that > software would recognize and take advantage of the hardware algorithm > without adding a special treatment for KVM. > (I'd vote for the simple pick-first-APIC lowest priority algorithm ... > I don't see much point in complicating lowest priority when it doesn't > deliver to lowest priority CPU anyway.) Vector hashing is an improvement for the common case where all vectors are set to all CPUs. Sure you can get an unlucky assignment, but it's still better than pick-first-APIC. Paolo -- 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/