From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 4AB2F7E9F for ; Tue, 14 Oct 2014 17:59:32 +0200 (CEST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 14 Oct 2014 09:00:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,718,1406617200"; d="scan'208";a="588800276" Received: from shvmail01.sh.intel.com ([10.239.29.42]) by orsmga001.jf.intel.com with ESMTP; 14 Oct 2014 09:04:07 -0700 Received: from shecgisg004.sh.intel.com (shecgisg004.sh.intel.com [10.239.29.89]) by shvmail01.sh.intel.com with ESMTP id s9EG42u4031659; Wed, 15 Oct 2014 00:04:02 +0800 Received: from shecgisg004.sh.intel.com (localhost [127.0.0.1]) by shecgisg004.sh.intel.com (8.13.6/8.13.6/SuSE Linux 0.8) with ESMTP id s9EG40Oh000881; Wed, 15 Oct 2014 00:04:02 +0800 Received: (from couyang@localhost) by shecgisg004.sh.intel.com (8.13.6/8.13.6/Submit) id s9EG4093000877; Wed, 15 Oct 2014 00:04:00 +0800 From: Ouyang Changchun To: dev@dpdk.org Date: Wed, 15 Oct 2014 00:03:54 +0800 Message-Id: <1413302634-848-1-git-send-email-changchun.ouyang@intel.com> X-Mailer: git-send-email 1.7.12.2 In-Reply-To: <1413299561-31263-1-git-send-email-changchun.ouyang@intel.com> References: <1413299561-31263-1-git-send-email-changchun.ouyang@intel.com> Subject: [dpdk-dev] [PATCH v4] virtio: Fix vring entry number issue 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: Tue, 14 Oct 2014 15:59:32 -0000 Fix one issue in virtio TX: it needs one more vring descriptor to hold the virtio header when transmitting packets, it is used later to determine whether to free more entries from used vring. It fixes failing to transmit any packet with 1 segment in the circumstance of only 1 descriptor in the vring free list. Signed-off-by: Changchun Ouyang Reviewed-by: Olivier Matz --- -V4 change: Relocate those changelog and annotation here. -V3 change: Resolve compilation issue due to mbuf re-structure. -V2 change: Refine description, 'vring descriptor' is more accurate than 'vring entry'; Accordingly update test condition (it needs one more descriptor for virtio header) to put packets to transmit queue. -V1 change: Fix the vring descriptor issue in virtio TX, it needs one more vring descriptor to hold the virtio header. lib/librte_pmd_virtio/virtio_rxtx.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/librte_pmd_virtio/virtio_rxtx.c b/lib/librte_pmd_virtio/virtio_rxtx.c index 0b10108..ac44c65 100644 --- a/lib/librte_pmd_virtio/virtio_rxtx.c +++ b/lib/librte_pmd_virtio/virtio_rxtx.c @@ -699,7 +699,8 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) num = (uint16_t)(likely(nb_used < VIRTIO_MBUF_BURST_SZ) ? nb_used : VIRTIO_MBUF_BURST_SZ); while (nb_tx < nb_pkts) { - int need = tx_pkts[nb_tx]->pkt.nb_segs - txvq->vq_free_cnt; + /* Need one more descriptor for virtio header. */ + int need = tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1; int deq_cnt = RTE_MIN(need, (int)num); num -= (deq_cnt > 0) ? deq_cnt : 0; @@ -708,7 +709,12 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) deq_cnt--; } - if (tx_pkts[nb_tx]->pkt.nb_segs <= txvq->vq_free_cnt) { + need = (int)tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1; + /* + * Zero or negative value indicates it has enough free + * decriptors to transmit. + */ + if (need <= 0) { txm = tx_pkts[nb_tx]; /* Enqueue Packet buffers */ error = virtqueue_enqueue_xmit(txvq, txm); -- 1.8.4.2