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From: Joyce Kong <joyce.kong@arm.com>
To: maxime.coquelin@redhat.com, chenbo.xia@intel.com,
	honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com
Cc: dev@dpdk.org, nd@arm.com
Subject: [dpdk-dev] [PATCH v1 3/8] vhost: remove unnecessary smp barrier for desc flags
Date: Mon, 21 Dec 2020 23:50:28 +0800
Message-ID: <20201221155033.6771-4-joyce.kong@arm.com> (raw)
In-Reply-To: <20201221155033.6771-1-joyce.kong@arm.com>

As function desc_is_avail performs a load-acquire barrier to
enforce the ordering between desc flags and desc content, it is
unnecessary to add a rte_smp_rmb barrier around the trace which
follows desc_is_avail.

Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 lib/librte_vhost/virtio_net.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6c5128665..ae6723766 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1281,8 +1281,6 @@ virtio_dev_rx_batch_packed(struct virtio_net *dev,
 			return -1;
 	}
 
-	rte_smp_rmb();
-
 	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
 		lens[i] = descs[avail_idx + i].len;
 
@@ -1343,7 +1341,6 @@ virtio_dev_rx_single_packed(struct virtio_net *dev,
 	struct buf_vector buf_vec[BUF_VECTOR_MAX];
 	uint16_t nr_descs = 0;
 
-	rte_smp_rmb();
 	if (unlikely(vhost_enqueue_single_packed(dev, vq, pkt, buf_vec,
 						 &nr_descs) < 0)) {
 		VHOST_LOG_DATA(DEBUG,
-- 
2.29.2


  parent reply	other threads:[~2020-12-21 15:52 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-21 15:50 [dpdk-dev] [PATCH v1 0/8] replace smp barriers in vhost with C11 atomic Joyce Kong
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 1/8] examples/vhost: relax memory ordering when enqueue/dequeue Joyce Kong
2021-01-07 16:33   ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 2/8] examples/vhost_blk: replace smp with thread fence Joyce Kong
2021-01-07 16:35   ` Maxime Coquelin
2020-12-21 15:50 ` Joyce Kong [this message]
2021-01-07 16:38   ` [dpdk-dev] [PATCH v1 3/8] vhost: remove unnecessary smp barrier for desc flags Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 4/8] vhost: remove unnecessary smp barrier for avail idx Joyce Kong
2021-01-07 16:43   ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 5/8] vhost: relax full barriers for desc flags Joyce Kong
2021-01-07 16:45   ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 6/8] vhost: relax full barriers for used idx Joyce Kong
2021-01-07 16:46   ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 7/8] vhost: replace smp with thread fence for packed vring Joyce Kong
2021-01-07 17:06   ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 8/8] vhost: replace smp with thread fence for control path Joyce Kong
2021-01-07 17:15   ` Maxime Coquelin
2021-01-08  9:16 ` [dpdk-dev] [PATCH v1 0/8] replace smp barriers in vhost with C11 atomic Maxime Coquelin

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