From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by dpdk.org (Postfix) with ESMTP id 99C0D4C97 for ; Fri, 1 Jun 2018 14:48:10 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 26D65401EF1B; Fri, 1 Jun 2018 12:48:10 +0000 (UTC) Received: from localhost.localdomain (ovpn-112-54.ams2.redhat.com [10.36.112.54]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2ABE020244E0; Fri, 1 Jun 2018 12:48:08 +0000 (UTC) From: Maxime Coquelin To: zhihong.wang@intel.com, tiwei.bie@intel.com, dev@dpdk.org Cc: Maxime Coquelin Date: Fri, 1 Jun 2018 14:47:54 +0200 Message-Id: <20180601124758.22652-1-maxime.coquelin@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 01 Jun 2018 12:48:10 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 01 Jun 2018 12:48:10 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'maxime.coquelin@redhat.com' RCPT:'' Subject: [dpdk-dev] [PATCH 0/4] net/virtio: Tx path selection and offload improvements X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Jun 2018 12:48:10 -0000 This series addresses a problem seen when running benchmars, where we see a big difference in Tx performance depending on whether Rx mergeable is enabled or not. With patch 1, Tx simple path is selected even when Rx-mrg is negotiated. Digging a bit further, I found that Tx simple path could be selected even when offload features had been negotiated. With patch 2, guest does not try to negotiate Tx offload features that haven't been selected by the application. It means that without restarting the guest, we can now switch from Tx simple path when application do no request offloads, to Tx standard path when the application request offloads. Note that to do so, one must stop the port first [0]. Another advantage of doing this than using Tx simple path when guest application does not use offload features, is that on host side, the virtio net header parsing is skipped in dequeue function. Patch 3 fixes an issue with Rx offload, as simple path was be used if application requested TCP LRO only. Finally, patch 4 aims at improving the offload feature checks in the standard paths. Below are benchmarks results when offloads are enabled at device level. Rx-mrg=off benchmarks: +------------+-------+-------------+-------------+----------+ | Run | PVP | Guest->Host | Host->Guest | Loopback | +------------+-------+-------------+-------------+----------+ | v18.05 | 14.47 | 17.02 | 17.57 | 13.15 | | + series | 14.88 | 19.64 | 17.63 | 13.11 | +------------+-------+-------------+-------------+----------+ Rx-mrg=on benchmarks: +------------+-------+-------------+-------------+----------+ | Run | PVP | Guest->Host | Host->Guest | Loopback | +------------+-------+-------------+-------------+----------+ | v18.05 | 9.53 | 13.80 | 16.70 | 13.11 | | + series | 12.62 | 19.69 | 16.70 | 13.11 | +------------+-------+-------------+-------------+----------+ [0]: testpmd> port start 0 EAL: Error disabling MSI-X interrupts for fd 17 set_rxtx_funcs(): virtio: using mergeable buffer Rx path on port 0 set_rxtx_funcs(): virtio: using simple Tx path on port 0 Port 0: 52:54:00:58:D7:01 Checking link statuses... Done testpmd> show port 0 tx_offload capabilities Tx Offloading Capabilities of port 0 : Per Queue : Per Port : VLAN_INSERT UDP_CKSUM TCP_CKSUM TCP_TSO MULTI_SEGS testpmd> show port 0 tx_offload configuration Tx Offloading Configuration of port 0 : Port : Queue[ 0] : testpmd> port stop 0 Stopping ports... Checking link statuses... Done testpmd> csum set tcp hw 0 Parse tunnel is off IP checksum offload is sw UDP checksum offload is sw TCP checksum offload is hw SCTP checksum offload is sw Outer-Ip checksum offload is sw testpmd> port start 0 Configuring Port 0 (socket 0) EAL: Error disabling MSI-X interrupts for fd 17 set_rxtx_funcs(): virtio: using mergeable buffer Rx path on port 0 set_rxtx_funcs(): virtio: using standard Tx path on port 0 Port 0: 52:54:00:58:D7:01 Checking link statuses... Done testpmd> show port 0 tx_offload configuration Tx Offloading Configuration of port 0 : Port : TCP_CKSUM Queue[ 0] : Maxime Coquelin (4): net/virtio: use simple path for Tx even if Rx mergeable net/vhost: improve Tx path selection net/virtio: don't use simple Rx path if TCP LRO requested net/virtio: improve offload check performance drivers/net/virtio/virtio_ethdev.c | 43 ++++++++++++++++++++++++++++++++++---- drivers/net/virtio/virtio_ethdev.h | 3 --- drivers/net/virtio/virtio_pci.h | 2 ++ drivers/net/virtio/virtio_rxtx.c | 29 ++++++------------------- 4 files changed, 47 insertions(+), 30 deletions(-) -- 2.14.3