From patchwork Thu Oct 31 11:47:07 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 287460 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3D4C52C03D5 for ; Thu, 31 Oct 2013 22:47:55 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752179Ab3JaLrd (ORCPT ); Thu, 31 Oct 2013 07:47:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50527 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103Ab3JaLr3 (ORCPT ); Thu, 31 Oct 2013 07:47:29 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r9VBlNxV021954 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 31 Oct 2013 07:47:24 -0400 Received: from jason-ThinkPad-T430s.redhat.com (dhcp-66-71-71.eng.nay.redhat.com [10.66.71.71] (may be forged)) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r9VBlFrp023775; Thu, 31 Oct 2013 07:47:20 -0400 From: Jason Wang To: davem@davemloft.net, edumazet@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, rusty@rustcorp.com.au, mst@redhat.com, mwdalton@google.com, virtualization@lists.linux-foundation.org Cc: kmindg@gmail.com, Jason Wang Subject: [PATCH net-next V2 2/2] virtio-net: coalesce rx frags when possible during rx Date: Thu, 31 Oct 2013 19:47:07 +0800 Message-Id: <1383220027-12278-2-git-send-email-jasowang@redhat.com> In-Reply-To: <1383220027-12278-1-git-send-email-jasowang@redhat.com> References: <1383220027-12278-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Commit 2613af0ed18a11d5c566a81f9a6510b73180660a (virtio_net: migrate mergeable rx buffers to page frag allocators) try to increase the payload/truesize for MTU-sized traffic. But this will introduce the extra overhead for GSO packets received because of the frag list. This commit tries to reduce this issue by coalesce the possible rx frags when possible during rx. Test result shows the about 15% improvement on full size GSO packet receiving (and even better than commit 2613af0ed18a11d5c566a81f9a6510b73180660a). Before this commit: ./netperf -H 192.168.100.4 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 20303.87 After this commit: ./netperf -H 192.168.100.4 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 23841.26 Cc: Rusty Russell Cc: Michael S. Tsirkin Cc: Michael Dalton Cc: Eric Dumazet Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang Acked-by: Eric Dumazet --- drivers/net/virtio_net.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 113ee93..5dc0de0 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -305,7 +305,7 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb) struct sk_buff *curr_skb = head_skb; char *buf; struct page *page; - int num_buf, len; + int num_buf, len, offset; num_buf = hdr->mhdr.num_buffers; while (--num_buf) { @@ -342,9 +342,15 @@ static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb) head_skb->truesize += MAX_PACKET_LEN; } page = virt_to_head_page(buf); - skb_add_rx_frag(curr_skb, num_skb_frags, page, - buf - (char *)page_address(page), len, - MAX_PACKET_LEN); + offset = buf - (char *)page_address(page); + if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) { + skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1, + len, MAX_PACKET_LEN); + } else { + skb_add_rx_frag(curr_skb, num_skb_frags, page, + offset, len, + MAX_PACKET_LEN); + } --rq->num; } return 0;