patch 'net/ixgbe: fix minimum Rx/Tx descriptors' has been queued to stable release 23.11.4

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 23.11.4

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 04/10/25. 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=05298e9879e2f51b87efdb91bc6b65336e5e423d

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 05298e9879e2f51b87efdb91bc6b65336e5e423d Mon Sep 17 00:00:00 2001
From: Mingjin Ye <mingjinx.ye at intel.com>
Date: Tue, 25 Feb 2025 09:12:36 +0000
Subject: [PATCH] net/ixgbe: fix minimum Rx/Tx descriptors
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit 6808ee1ceddc76846f80ae3d05aad374a34a1754 ]

The minimum free packet threshold (tx_free_thresh) and the minimum RS bit
threshold (tx_rs_thresh) both have a default value of 32. Therefore, the
default minimum number of ring descriptors value is 64.

For reference, see "Configuration of Transmit Queues" in
doc/guides/prog_guide/ethdev/ethdev.rst

Fixes: dee5f1fd5fc7 ("ixgbe: get queue info and descriptor limits")

Signed-off-by: Mingjin Ye <mingjinx.ye at intel.com>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
---
 doc/guides/nics/ixgbe.rst      | 8 +++-----
 drivers/net/ixgbe/ixgbe_rxtx.h | 2 +-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/doc/guides/nics/ixgbe.rst b/doc/guides/nics/ixgbe.rst
index e32eff6244..d54c20e1ea 100644
--- a/doc/guides/nics/ixgbe.rst
+++ b/doc/guides/nics/ixgbe.rst
@@ -68,13 +68,11 @@ Ensure that the following pre-conditions are satisfied:
 
 *   (rxq->nb_rx_desc % rxq->rx_free_thresh) == 0
 
-*   rxq->nb_rx_desc  < (IXGBE_MAX_RING_DESC - RTE_PMD_IXGBE_RX_MAX_BURST)
+*   rxq->nb_rx_desc >= IXGBE_MIN_RING_DESC
 
-These conditions are checked in the code.
+*   rxq->nb_rx_desc <= IXGBE_MAX_RING_DESC
 
-Scattered packets are not supported in this mode.
-If an incoming packet is greater than the maximum acceptable length of one "mbuf" data size (by default, the size is 2 KB),
-vPMD for RX would be disabled.
+These conditions are checked in the code.
 
 By default, IXGBE_MAX_RING_DESC is set to 4096 and RTE_PMD_IXGBE_RX_MAX_BURST is set to 32.
 
diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
index ee89c89929..78f17a0825 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.h
+++ b/drivers/net/ixgbe/ixgbe_rxtx.h
@@ -24,7 +24,7 @@
  * descriptors should meet the following condition:
  *      (num_ring_desc * sizeof(rx/tx descriptor)) % 128 == 0
  */
-#define	IXGBE_MIN_RING_DESC	32
+#define	IXGBE_MIN_RING_DESC	64
 #define	IXGBE_MAX_RING_DESC	4096
 
 #define RTE_PMD_IXGBE_TX_MAX_BURST 32
-- 
2.34.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2025-04-08 15:39:06.539412783 +0800
+++ 0018-net-ixgbe-fix-minimum-Rx-Tx-descriptors.patch	2025-04-08 15:39:05.916436584 +0800
@@ -1 +1 @@
-From 6808ee1ceddc76846f80ae3d05aad374a34a1754 Mon Sep 17 00:00:00 2001
+From 05298e9879e2f51b87efdb91bc6b65336e5e423d Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit 6808ee1ceddc76846f80ae3d05aad374a34a1754 ]
@@ -14 +16,0 @@
-Cc: stable at dpdk.org
@@ -19,2 +21,2 @@
- doc/guides/nics/ixgbe.rst            | 8 +++-----
- drivers/net/intel/ixgbe/ixgbe_rxtx.h | 2 +-
+ doc/guides/nics/ixgbe.rst      | 8 +++-----
+ drivers/net/ixgbe/ixgbe_rxtx.h | 2 +-
@@ -24 +26 @@
-index 8dcde7ae1c..a03ec7a7e8 100644
+index e32eff6244..d54c20e1ea 100644
@@ -42 +44 @@
- By default, IXGBE_MAX_RING_DESC is set to 8192 and RTE_PMD_IXGBE_RX_MAX_BURST is set to 32.
+ By default, IXGBE_MAX_RING_DESC is set to 4096 and RTE_PMD_IXGBE_RX_MAX_BURST is set to 32.
@@ -44,5 +46,5 @@
-diff --git a/drivers/net/intel/ixgbe/ixgbe_rxtx.h b/drivers/net/intel/ixgbe/ixgbe_rxtx.h
-index 278f665108..54569c7ade 100644
---- a/drivers/net/intel/ixgbe/ixgbe_rxtx.h
-+++ b/drivers/net/intel/ixgbe/ixgbe_rxtx.h
-@@ -26,7 +26,7 @@
+diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
+index ee89c89929..78f17a0825 100644
+--- a/drivers/net/ixgbe/ixgbe_rxtx.h
++++ b/drivers/net/ixgbe/ixgbe_rxtx.h
+@@ -24,7 +24,7 @@
@@ -54 +56 @@
- #define	IXGBE_MAX_RING_DESC	8192
+ #define	IXGBE_MAX_RING_DESC	4096