From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC145C4321E for ; Fri, 7 Sep 2018 07:33:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF2F720878 for ; Fri, 7 Sep 2018 07:33:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF2F720878 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727760AbeIGMMx (ORCPT ); Fri, 7 Sep 2018 08:12:53 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:52542 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725940AbeIGMMx (ORCPT ); Fri, 7 Sep 2018 08:12:53 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9211926368; Fri, 7 Sep 2018 07:33:15 +0000 (UTC) Received: from [10.72.12.68] (ovpn-12-68.pek2.redhat.com [10.72.12.68]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 40E3C112C247; Fri, 7 Sep 2018 07:33:10 +0000 (UTC) Subject: Re: [PATCH net-next 09/11] tuntap: accept an array of XDP buffs through sendmsg() To: "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org References: <20180906040526.22518-1-jasowang@redhat.com> <20180906040526.22518-10-jasowang@redhat.com> <20180906134834-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Fri, 7 Sep 2018 15:33:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180906134834-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 07 Sep 2018 07:33:15 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 07 Sep 2018 07:33:15 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jasowang@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年09月07日 01:51, Michael S. Tsirkin wrote: > On Thu, Sep 06, 2018 at 12:05:24PM +0800, Jason Wang wrote: >> This patch implement TUN_MSG_PTR msg_control type. This type allows >> the caller to pass an array of XDP buffs to tuntap through ptr field >> of the tun_msg_control. If an XDP program is attached, tuntap can run >> XDP program directly. If not, tuntap will build skb and do a fast >> receiving since part of the work has been done by vhost_net. >> >> This will avoid lots of indirect calls thus improves the icache >> utilization and allows to do XDP batched flushing when doing XDP >> redirection. >> >> Signed-off-by: Jason Wang > Is most of the benefit in batched flushing or skipping > indirect calls? Because if it's flushing we can gain > most of it easily by adding an analog of xmit_more. > Should be both. XDP_DROP doesn't flush but it gives obvious improvement. Thanks