From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Coquelin Subject: [PATCH 5/7] vhost: improve prefetching in dequeue path Date: Fri, 8 Jun 2018 12:39:11 +0200 Message-ID: <20180608103913.11517-6-maxime.coquelin@redhat.com> References: <20180608103913.11517-1-maxime.coquelin@redhat.com> Cc: Maxime Coquelin To: zhihong.wang@intel.com, tiwei.bie@intel.com, dev@dpdk.org Return-path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by dpdk.org (Postfix) with ESMTP id 64BA569F7 for ; Fri, 8 Jun 2018 12:39:48 +0200 (CEST) In-Reply-To: <20180608103913.11517-1-maxime.coquelin@redhat.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" This is an optimization to prefetch next buffer while the current one is being processed. Signed-off-by: Maxime Coquelin --- lib/librte_vhost/virtio_net.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index 09272aba2..6e4004666 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -895,7 +895,13 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, buf_iova = buf_vec[vec_idx].buf_iova; buf_len = buf_vec[vec_idx].buf_len; - rte_prefetch0((void *)(uintptr_t)buf_addr); + /* + * Prefecth desc n + 1 buffer while + * desc n buffer is processed. + */ + if (vec_idx + 1 < nr_vec) + rte_prefetch0((void *)(uintptr_t) + buf_vec[vec_idx + 1].buf_addr); buf_offset = 0; buf_avail = buf_len; @@ -1127,6 +1133,8 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id, if (likely(dev->dequeue_zero_copy == 0)) update_shadow_used_ring(vq, head_idx, 0); + rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr); + pkts[i] = rte_pktmbuf_alloc(mbuf_pool); if (unlikely(pkts[i] == NULL)) { RTE_LOG(ERR, VHOST_DATA, -- 2.14.3