patch 'net/virtio: revert Tx free threshold fix' has been queued to stable release 23.11.5

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 23.11.5

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/10/25. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://git.dpdk.org/dpdk-stable/log/?h=23.11-staging

This queued commit can be viewed at:
https://git.dpdk.org/dpdk-stable/commit/?h=23.11-staging&id=5dce28bed67705d012acb4670ed99d547b7c96f6

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 5dce28bed67705d012acb4670ed99d547b7c96f6 Mon Sep 17 00:00:00 2001
From: David Marchand <david.marchand at redhat.com>
Date: Tue, 8 Jul 2025 16:07:09 +0200
Subject: [PATCH] net/virtio: revert Tx free threshold fix
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit 5a117f05fc5ad200ec61837fa21d946c6a209822 ]

This fix introduced a performance regression.

The problem is under investigation, but we are too close to the release
(and the virtio/vhost maintainer is not available) to get a fix before
the v25.07 release.

Revert this change for now, we can revisit during v25.11.

Bugzilla ID: 1747
Fixes: 3e3c7f3fa5ac ("net/virtio: fix check of threshold for Tx freeing")
Cc: stable at dpdk.org

Signed-off-by: David Marchand <david.marchand at redhat.com>
Acked-by: Hengqi Chen <hengqi.chen at gmail.com>
---
 drivers/net/virtio/virtio_rxtx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index a13df4952d..99b95194cd 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -1863,7 +1863,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 
 	nb_used = virtqueue_nused(vq);
 
-	if (likely(vq->vq_free_cnt < vq->vq_free_thresh))
+	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
 		virtio_xmit_cleanup(vq, nb_used);
 
 	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
-- 
2.34.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2025-07-30 22:50:04.356999507 +0800
+++ 0020-net-virtio-revert-Tx-free-threshold-fix.patch	2025-07-30 22:50:03.052760197 +0800
@@ -1 +1 @@
-From 5a117f05fc5ad200ec61837fa21d946c6a209822 Mon Sep 17 00:00:00 2001
+From 5dce28bed67705d012acb4670ed99d547b7c96f6 Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit 5a117f05fc5ad200ec61837fa21d946c6a209822 ]
@@ -25 +28 @@
-index ab97f03d7d..edecd2011f 100644
+index a13df4952d..99b95194cd 100644
@@ -28 +31 @@
-@@ -1873,7 +1873,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
+@@ -1863,7 +1863,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)