From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id 86DC36A94 for ; Fri, 19 Aug 2016 14:51:59 +0200 (CEST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP; 19 Aug 2016 05:51:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,544,1464678000"; d="scan'208";a="1038480391" Received: from unknown (HELO dpdk5.sh.intel.com) ([10.239.129.118]) by orsmga002.jf.intel.com with ESMTP; 19 Aug 2016 05:51:50 -0700 From: Zhihong Wang To: dev@dpdk.org Cc: maxime.coquelin@redhat.com, yuanhan.liu@linux.intel.com, Zhihong Wang Date: Fri, 19 Aug 2016 01:43:48 -0400 Message-Id: <1471585430-125925-4-git-send-email-zhihong.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1471585430-125925-1-git-send-email-zhihong.wang@intel.com> References: <1471319402-112998-1-git-send-email-zhihong.wang@intel.com> <1471585430-125925-1-git-send-email-zhihong.wang@intel.com> Subject: [dpdk-dev] [PATCH v3 3/5] vhost: add desc prefetch 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: Fri, 19 Aug 2016 12:52:02 -0000 This patch adds descriptor prefetch to hide cache access latency. Signed-off-by: Zhihong Wang --- lib/librte_vhost/vhost_rxtx.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c index b09a9c3..7523b2d 100644 --- a/lib/librte_vhost/vhost_rxtx.c +++ b/lib/librte_vhost/vhost_rxtx.c @@ -131,6 +131,11 @@ loop_check(struct vhost_virtqueue *vq, uint16_t avail_idx, uint32_t pkt_left) if (pkt_left == 0 || avail_idx == vq->last_used_idx) return 1; + /* prefetch the next desc */ + if (pkt_left > 1 && avail_idx != vq->last_used_idx + 1) + rte_prefetch0(&vq->desc[vq->avail->ring[ + (vq->last_used_idx + 1) & (vq->size - 1)]]); + return 0; } -- 2.7.4