From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 339215936 for ; Sun, 18 Oct 2015 08:28:45 +0200 (CEST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP; 17 Oct 2015 23:28:45 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,696,1437462000"; d="scan'208";a="583064446" Received: from shvmail01.sh.intel.com ([10.239.29.42]) by FMSMGA003.fm.intel.com with ESMTP; 17 Oct 2015 23:28:43 -0700 Received: from shecgisg003.sh.intel.com (shecgisg003.sh.intel.com [10.239.29.90]) by shvmail01.sh.intel.com with ESMTP id t9I6SgPq023384 for ; Sun, 18 Oct 2015 14:28:42 +0800 Received: from shecgisg003.sh.intel.com (localhost [127.0.0.1]) by shecgisg003.sh.intel.com (8.13.6/8.13.6/SuSE Linux 0.8) with ESMTP id t9I6Senv003210 for ; Sun, 18 Oct 2015 14:28:42 +0800 Received: (from hxie5@localhost) by shecgisg003.sh.intel.com (8.13.6/8.13.6/Submit) id t9I6SeVO003206 for dev@dpdk.org; Sun, 18 Oct 2015 14:28:40 +0800 From: Huawei Xie To: dev@dpdk.org Date: Sun, 18 Oct 2015 14:28:25 +0800 Message-Id: <1445149720-3172-1-git-send-email-huawei.xie@intel.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1443537953-23917-1-git-send-email-huawei.xie@intel.com> References: <1443537953-23917-1-git-send-email-huawei.xie@intel.com> Subject: [dpdk-dev] [PATCH v2 0/7] virtio ring layout optimization and simple rx/tx processing X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Oct 2015 06:28:45 -0000 In DPDK based switching enviroment, mostly vhost runs on a dedicated core while virtio processing in guest VMs runs on different cores. Take RX for example, with generic implementation, for each guest buffer, a) virtio driver allocates a descriptor from free descriptor list b) modify the entry of avail ring to point to allocated descriptor c) after packet is received, free the descriptor When vhost fetches the avail ring, it needs to fetch the modified L1 cache from virtio core, which is a heavy cost in current CPU implementation. This idea of this optimization is: allocate the fixed descriptor for each entry of avail ring. and avail ring will always be the same during the run. This removes L1 cache transfer from virtio core to vhost core for avail ring. Besides, no descriptor free and allocation is needed. Most importantly, this makes vector procesing possible to further accelerate the processing. This is the layout for the avail ring(take 256 ring entries for example), with each entry pointing to the descriptor with the same index. avail idx + | +----+----+---+-------------+------+ | 0 | 1 | 2 | ... | 254 | 255 | avail ring +-+--+-+--+-+-+---------+---+--+---+ | | | | | | | | | | | | v v v | v v +-+--+-+--+-+-+---------+---+--+---+ | 0 | 1 | 2 | ... | 254 | 255 | desc ring +----+----+---+-------------+------+ | | +----+----+---+-------------+------+ | 0 | 1 | 2 | | 254 | 255 | used ring +----+----+---+-------------+------+ | + This is the ring layout for TX. As we need one virtio header for each xmit packet, we have 128 slots available. ++ || || +-----+-----+-----+--------------+------+------+------+ | 0 | 1 | ... | 127 || 128 | 129 | ... | 255 | avail ring +--+--+--+--+-----+---+------+---+--+---+------+--+---+ | | | || | | | v v v || v v v +--+--+--+--+-----+---+------+---+--+---+------+--+---+ | 127 | 128 | ... | 255 || 127 | 128 | ... | 255 | desc ring for virtio_net_hdr +--+--+--+--+-----+---+------+---+--+---+------+--+---+ | | | || | | | v v v || v v v +--+--+--+--+-----+---+------+---+--+---+------+--+---+ | 0 | 1 | ... | 127 || 0 | 1 | ... | 127 | desc ring for tx dat +-----+-----+-----+--------------+------+------+------+ || || ++ Performance boost could be observed only if the virtio backend isn't the bottleneck or in VM2VM case. There are also several vhost optimization patches to be submitted later. Changes in v2: - Remove the configure macro - Enable simple R/TX processing when user specifies simple txq flags - Reword some comments and commit messages Huawei Xie (7): virtio: add virtio_rxtx.h header file virtio: add software rx ring, fake_buf into virtqueue virtio: rx/tx ring layout optimization virtio: fill RX avail ring with blank mbufs virtio: virtio vec rx virtio: simple tx routine virtio: pick simple rx/tx func drivers/net/virtio/Makefile | 2 +- drivers/net/virtio/virtio_ethdev.c | 13 ++ drivers/net/virtio/virtio_ethdev.h | 5 + drivers/net/virtio/virtio_rxtx.c | 53 ++++- drivers/net/virtio/virtio_rxtx.h | 39 ++++ drivers/net/virtio/virtio_rxtx_simple.c | 403 ++++++++++++++++++++++++++++++++ drivers/net/virtio/virtqueue.h | 5 + 7 files changed, 517 insertions(+), 3 deletions(-) create mode 100644 drivers/net/virtio/virtio_rxtx.h create mode 100644 drivers/net/virtio/virtio_rxtx_simple.c -- 1.8.1.4