From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936360AbcLOOcu (ORCPT ); Thu, 15 Dec 2016 09:32:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44600 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932591AbcLOOcs (ORCPT ); Thu, 15 Dec 2016 09:32:48 -0500 Subject: Re: [PATCH v2] KVM: x86: avoid redundant REQ_EVENT To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Roman Kagan , Denis Plotnikov , den@virtuozzo.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20161214105908.322638-1-dplotnikov@virtuozzo.com> <20161215071840.GB7704@rkaganb.sw.ru> <20161215143054.GC6667@potion> From: Paolo Bonzini Message-ID: <4876bc4a-b72a-897e-84a7-c34c3f934705@redhat.com> Date: Thu, 15 Dec 2016 15:32:45 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20161215143054.GC6667@potion> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 15 Dec 2016 14:32:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/12/2016 15:30, Radim Krčmář wrote: > > One useless round of KVM_REQ_EVENT is not going change nested > performance by much and it is not the only thing we could improve wrt. > TPR ... I would just leave it for now and take care of it when we > * don't to update PPR at all with APICv -- it is already correct > * drop the KVM_REQ_EVENT with flex priority, because lower TPR cannot > unmask an interrupt I agree. I still don't like the patch very much, because I feel like an explicit state machine ("can KVM_REQ_EVENT do anything?") would be more maintainable. But if I don't come up with anything we'll go with this patch. Paolo