From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751687AbdIUGgh (ORCPT ); Thu, 21 Sep 2017 02:36:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49114 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751436AbdIUGgf (ORCPT ); Thu, 21 Sep 2017 02:36:35 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C323B90901 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eric.auger@redhat.com Subject: Re: [PATCH] vfio/pci: Virtualize Maximum Payload Size To: Sinan Kaya , Alex Williamson References: <20170919164952.13200.78849.stgit@gimli.home> <20170919142024.05723289@t450s.home> <3dd92928-3cda-50c1-6a67-10721c003c10@redhat.com> <73d55003-6fcd-3741-73a1-365c73933538@redhat.com> <20170920101133.33b68d8f@w520.home> <2c094ad6-4641-ebee-7faa-21ad9beeca72@codeaurora.org> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jcm@redhat.com, "linux-pci@vger.kernel.org" From: Auger Eric Message-ID: Date: Thu, 21 Sep 2017 08:36:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <2c094ad6-4641-ebee-7faa-21ad9beeca72@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 21 Sep 2017 06:36:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sinan, On 20/09/2017 18:29, Sinan Kaya wrote: > On 9/20/2017 12:11 PM, Alex Williamson wrote: >> My impression is that the issue would be inefficiency. There should be >> nothing functionally wrong with a read request less than MPS, but we're >> not "filling" the TLP as much as the topology allows. Is that your >> understanding as well, Sinan? > > That's my understanding as well. It would be a performance hit to use a > value less than MPS. > > Thank you for your explanations. best Regards Eric