mlx: add known issues in release notes

Signed-off-by: Olga Shern <olgas@mellanox.com>

diff --git a/doc/guides/rel_notes/release_2_2.rst b/doc/guides/rel_notes/release_2_2.rst
index 10e0907..8bad64d 100644 (file)
--- a/doc/guides/rel_notes/release_2_2.rst
+++ b/doc/guides/rel_notes/release_2_2.rst
@@ -417,6 +417,18 @@ Known Issues
   As the l3fwd example application requires this info, the i40e vector
   driver must be disabled to benefit of the packet type with i40e.
 
   As the l3fwd example application requires this info, the i40e vector
   driver must be disabled to benefit of the packet type with i40e.
 

+* **Mellanox PMDs (mlx4 & mlx5):**
+
+  * PMDs do not support DPDK integrated shared library.
+
+  * There is performance degradation for small packets when PMD
+    is compiled with SGE_WR_N = 4 compared to the performance when SGE_WR_N = 1.
+    If scattered packets are not used it is recomended
+    to compile PMD with SGE_WR_N = 1.
+
+  * When a Multicast or Broadcast packet is sent to the SR-IOV mlx4 VF,
+    it is returned back to the port.
+

 
 API Changes
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 API Changes
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