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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 22BD1C433FF for ; Thu, 15 Aug 2019 09:55:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F140821855 for ; Thu, 15 Aug 2019 09:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731034AbfHOJz3 (ORCPT ); Thu, 15 Aug 2019 05:55:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44180 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726098AbfHOJz3 (ORCPT ); Thu, 15 Aug 2019 05:55:29 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2B76E804F2; Thu, 15 Aug 2019 09:55:29 +0000 (UTC) Received: from [10.72.12.184] (ovpn-12-184.pek2.redhat.com [10.72.12.184]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B425608AB; Thu, 15 Aug 2019 09:55:20 +0000 (UTC) Subject: Re: [PATCH v2] virtio-net: lower min ring num_free for efficiency To: ? jiang , "mst@redhat.com" Cc: "davem@davemloft.net" , "ast@kernel.org" , "daniel@iogearbox.net" , "jakub.kicinski@netronome.com" , "hawk@kernel.org" , "john.fastabend@gmail.com" , "kafai@fb.com" , "songliubraving@fb.com" , "yhs@fb.com" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "xdp-newbies@vger.kernel.org" , "bpf@vger.kernel.org" , "jiangran.jr@alibaba-inc.com" References: From: Jason Wang Message-ID: Date: Thu, 15 Aug 2019 17:55:17 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 15 Aug 2019 09:55:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/8/15 下午5:42, ? jiang wrote: > This change lowers ring buffer reclaim threshold from 1/2*queue to budget > for better performance. According to our test with qemu + dpdk, packet > dropping happens when the guest is not able to provide free buffer in > avail ring timely with default 1/2*queue. The value in the patch has been > tested and does show better performance. > > Test setup: iperf3 to generate packets to guest (total 30mins, pps 400k, UDP) > avg packets drop before: 2842 > avg packets drop after: 360(-87.3%) > > Signed-off-by: jiangkidd > --- > drivers/net/virtio_net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 0d4115c9e20b..bc08be7925eb 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1331,7 +1331,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget, > } > } > > - if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) { > + if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) { > if (!try_fill_recv(vi, rq, GFP_ATOMIC)) > schedule_delayed_work(&vi->refill, 0); > } Acked-by: Jason Wang