From patchwork Fri Aug 15 03:40:08 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 380066 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 0266214008C for ; Fri, 15 Aug 2014 13:40:41 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932194AbaHODkV (ORCPT ); Thu, 14 Aug 2014 23:40:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65262 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754589AbaHODkT (ORCPT ); Thu, 14 Aug 2014 23:40:19 -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 s7F3eGbS026791 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Aug 2014 23:40:17 -0400 Received: from jason-ThinkPad-T430s.redhat.com (vpn1-114-17.nay.redhat.com [10.66.114.17]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s7F3eBEn001123; Thu, 14 Aug 2014 23:40:12 -0400 From: Jason Wang To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang Subject: [PATCH net-next] vhost_net: stop rx net polling when possible Date: Fri, 15 Aug 2014 11:40:08 +0800 Message-Id: <1408074008-4357-1-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 After rx vq was enabled, we never stop polling its socket. This is sub optimal when may lead unnecessary wake-ups after the rx net work has already been queued. This could be optimized by stopping polling the rx net sock when processing both rx and tx and restart it afterward. This could save unnecessary wake-ups and even unnecessary spin locks acquiring with the help of commit 9e641bdcfa4ef4d6e2fbaa59c1be0ad5d1551fd5 "net-tun: restructure tun_do_read for better sleep/wakeup efficiency". Test shows significant CPU% savings during almost all the cases: Guest rx stream: size(B)/sessions/throughput/cpu/normalized thru/ 64/1/+0.7773% -8.6224% +10.2866% 64/2/+0.6335% -13.9109% +16.8946% 64/4/-0.8182% -14.8336% +16.4565% 64/8/+0.4830% -13.7675% +16.5256% 256/1/-7.0963% -12.6880% +6.4043% 256/2/-1.3982% -11.5424% +11.4678% 256/4/-0.0350% -11.8323% +13.3806% 256/8/-1.5830% -12.7693% +12.8238% 1024/1/-7.4895% -19.1449% +14.4152% 1024/2/-7.4575% -19.4018% +14.8195% 1024/4/-0.3881% -9.1183% +9.6061% 1024/8/+0.4713% -11.0155% +12.9087% 4096/1/+0.8786% -8.4050% +10.1355% 4096/2/+0.0098% -15.3094% +18.0885% 4096/4/+0.0445% -10.8247% +12.1886% 4096/8/-2.1317% -12.5111% +11.8637% 16384/1/-0.0008% -6.1891% +6.5966% 16384/2/-0.0117% -16.2716% +19.4198% 16384/4/+0.0001% -5.9197% +6.2923% 16384/8/+0.0173% -7.6681% +8.3236% 65535/1/+0.0011% -10.3594% +11.5578% 65535/2/-0.4108% -14.4304% +16.3838% 65535/4/+0.0011% -10.3594% +11.5578% 65535/8/-0.4108% -14.4304% +16.3838% Guest tx stream: size(B)/sessions/throughput/cpu/normalized thru/ 64/1/-0.6228% -2.1936% +1.6060% 64/2/+0.8646% -3.5063% +4.5297% 64/4/+0.8733% -3.2495% +4.2613% 64/8/+1.4290% -3.5593% +5.1724% 256/1/+7.2098% -3.1122% +10.6535% 256/2/-10.1408% -6.8230% -3.5607% 256/4/-11.3531% -6.7085% -4.9785% 256/8/-10.2723% -6.5628% -3.9701% 1024/1/-18.9329% -13.6162% -6.1547% 1024/2/-0.3728% -1.3181% +0.9580% 1024/4/+0.0125% -3.6338% +3.7838% 1024/8/-0.0030% -2.7282% +2.8017% 4096/1/+16.9367% -1.9435% +19.2543% 4096/2/+0.0121% -6.1682% +6.5866% 4096/4/+0.0019% -3.8510% +4.0072% 4096/8/-0.0222% -4.1368% +4.2922% 16384/1/-0.0026% -8.6892% +9.5132% 16384/2/-0.0012% -10.1676% +11.3171% 16384/4/+0.0196% -1.2551% +1.2908% 16384/8/+0.1303% -3.2634% +3.5082% 65535/1/+0.0019% -3.4694% +3.5961% 65535/2/-0.0003% -0.7635% +0.7690% 65535/4/-0.0219% -2.7875% +2.8448% 65535/8/+0.1137% -2.7922% +2.9894% TCP_RR: size(B)/sessions/throughput/cpu/normalized thru/ 256/1/+1.9004% -4.7985% +7.0366% 256/25/-4.7366% -11.0809% +7.1349% 256/50/+3.9808% -5.2037% +9.6887% 4096/1/+2.1619% -0.7303% +2.9134% 4096/25/-13.1836% -14.7298% +1.8134% 4096/50/-11.1990% -15.4763% +5.0605% Signed-off-by: Jason Wang --- drivers/vhost/net.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 8dae2f7..d4a9742 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -334,6 +334,8 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) static void handle_tx(struct vhost_net *net) { struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *rx_vq = &net->vqs[VHOST_NET_VQ_RX].vq; + struct vhost_poll *rx_poll = &net->poll[VHOST_NET_VQ_RX]; struct vhost_virtqueue *vq = &nvq->vq; unsigned out, in, s; int head; @@ -348,15 +350,18 @@ static void handle_tx(struct vhost_net *net) size_t len, total_len = 0; int err; size_t hdr_size; - struct socket *sock; + struct socket *sock, *rxsock; struct vhost_net_ubuf_ref *uninitialized_var(ubufs); - bool zcopy, zcopy_used; + bool zcopy, zcopy_used, poll = false; mutex_lock(&vq->mutex); + mutex_lock(&rx_vq->mutex); sock = vq->private_data; + rxsock = rx_vq->private_data; if (!sock) goto out; + vhost_poll_stop(rx_poll); vhost_disable_notify(&net->dev, vq); hdr_size = nvq->vhost_hlen; @@ -451,11 +456,17 @@ static void handle_tx(struct vhost_net *net) total_len += len; vhost_net_tx_packet(net); if (unlikely(total_len >= VHOST_NET_WEIGHT)) { - vhost_poll_queue(&vq->poll); + poll = true; break; } } + + if (rxsock) + vhost_poll_start(rx_poll, rxsock->file); + if (poll) + vhost_poll_queue(&vq->poll); out: + mutex_unlock(&rx_vq->mutex); mutex_unlock(&vq->mutex); } @@ -554,6 +565,7 @@ err: static void handle_rx(struct vhost_net *net) { struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; + struct vhost_poll *poll = &net->poll[VHOST_NET_VQ_RX]; struct vhost_virtqueue *vq = &nvq->vq; unsigned uninitialized_var(in), log; struct vhost_log *vq_log; @@ -580,6 +592,8 @@ static void handle_rx(struct vhost_net *net) sock = vq->private_data; if (!sock) goto out; + + vhost_poll_stop(poll); vhost_disable_notify(&net->dev, vq); vhost_hlen = nvq->vhost_hlen; @@ -660,10 +674,12 @@ static void handle_rx(struct vhost_net *net) vhost_log_write(vq, vq_log, log, vhost_len); total_len += vhost_len; if (unlikely(total_len >= VHOST_NET_WEIGHT)) { - vhost_poll_queue(&vq->poll); - break; + vhost_poll_queue(poll); + goto out; } } + + vhost_poll_start(poll, sock->file); out: mutex_unlock(&vq->mutex); }