From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Coquelin Subject: [PATCH v2] vhost: Only access header if offloading is supported in dequeue path Date: Tue, 11 Oct 2016 09:45:27 +0200 Message-ID: <1476171927-10134-1-git-send-email-maxime.coquelin@redhat.com> References: <1475773241-5714-1-git-send-email-maxime.coquelin@redhat.com> Cc: mst@redhat.com, jianfeng.tan@intel.com, olivier.matz@6wind.com, stephen@networkplumber.org, Maxime Coquelin To: yuanhan.liu@linux.intel.com, dev@dpdk.org Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 2FC376CB4 for ; Tue, 11 Oct 2016 09:45:34 +0200 (CEST) In-Reply-To: <1475773241-5714-1-git-send-email-maxime.coquelin@redhat.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" If offloading features are not negotiated, parsing the virtio header is not needed. Micro-benchmark with testpmd shows that the gain is +4% with indirect descriptors, +1% when using direct descriptors. Signed-off-by: Maxime Coquelin --- Changes since v1: ================= - Rebased - Fix early out check in vhost_dequeue_offload lib/librte_vhost/virtio_net.c | 47 ++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index a59c39b..5e2fd75 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -548,6 +548,18 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id, return virtio_dev_rx(dev, queue_id, pkts, count); } +static inline bool +virtio_net_with_host_offload(struct virtio_net *dev) +{ + if (dev->features & + (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_ECN | + VIRTIO_NET_F_HOST_TSO4 | VIRTIO_NET_F_HOST_TSO6 | + VIRTIO_NET_F_HOST_UFO)) + return true; + + return false; +} + static void parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr) { @@ -600,6 +612,9 @@ vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m) void *l4_hdr = NULL; struct tcp_hdr *tcp_hdr = NULL; + if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE) + return; + parse_ethernet(m, &l4_proto, &l4_hdr); if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (hdr->csum_start == (m->l2_len + m->l3_len)) { @@ -684,12 +699,12 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs, struct rte_mempool *mbuf_pool) { struct vring_desc *desc; - uint64_t desc_addr; + uint64_t desc_addr = 0; uint32_t desc_avail, desc_offset; uint32_t mbuf_avail, mbuf_offset; uint32_t cpy_len; struct rte_mbuf *cur = m, *prev = m; - struct virtio_net_hdr *hdr; + struct virtio_net_hdr *hdr = NULL; /* A counter to avoid desc dead loop chain */ uint32_t nr_desc = 1; @@ -698,12 +713,14 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs, (desc->flags & VRING_DESC_F_INDIRECT)) return -1; - desc_addr = gpa_to_vva(dev, desc->addr); - if (unlikely(!desc_addr)) - return -1; + if (virtio_net_with_host_offload(dev)) { + desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; - hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); - rte_prefetch0(hdr); + hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr); + rte_prefetch0(hdr); + } /* * A virtio driver normally uses at least 2 desc buffers @@ -720,18 +737,24 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs, if (unlikely(!desc_addr)) return -1; - rte_prefetch0((void *)(uintptr_t)desc_addr); - desc_offset = 0; desc_avail = desc->len; nr_desc += 1; - - PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0); } else { + if (!desc_addr) { + desc_addr = gpa_to_vva(dev, desc->addr); + if (unlikely(!desc_addr)) + return -1; + } + desc_avail = desc->len - dev->vhost_hlen; desc_offset = dev->vhost_hlen; } + rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset)); + + PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0); + mbuf_offset = 0; mbuf_avail = m->buf_len - RTE_PKTMBUF_HEADROOM; while (1) { @@ -795,7 +818,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs, prev->data_len = mbuf_offset; m->pkt_len += mbuf_offset; - if (hdr->flags != 0 || hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) + if (virtio_net_with_host_offload(dev)) vhost_dequeue_offload(hdr, m); return 0; -- 2.7.4