[v4,3/3] gso: update documents for UDP/IPv4 GSO
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Commit Message
This patch updates the programmer guide and testpmd user guide for
UDP/IPv4 GSO.
Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
Acked-by: Xiao Wang <xiao.w.wang@intel.com>
---
doc/guides/prog_guide/generic_segmentation_offload_lib.rst | 10 ++++++++++
doc/guides/testpmd_app_ug/testpmd_funcs.rst | 7 +++++++
2 files changed, 17 insertions(+)
@@ -43,6 +43,7 @@ Limitations
#. Currently, the GSO library supports the following IPv4 packet types:
- TCP
+ - UDP
- VxLAN
- GRE
@@ -146,6 +147,15 @@ TCP/IPv4 GSO
TCP/IPv4 GSO supports segmentation of suitably large TCP/IPv4 packets, which
may also contain an optional VLAN tag.
+UDP/IPv4 GSO
+~~~~~~~~~~~~
+UDP/IPv4 GSO supports segmentation of suitably large UDP/IPv4 packets, which
+may also contain an optional VLAN tag. UDP GSO is the same as IP fragmentation.
+Specifically, UDP GSO treats the UDP header as a part of the payload and
+does not modify it during segmentation. Therefore, after UDP GSO, only the
+first output packet has the original UDP header, and others just have l2
+and l3 headers.
+
VxLAN GSO
~~~~~~~~~
VxLAN packets GSO supports segmentation of suitably large VxLAN packets,
@@ -1059,6 +1059,13 @@ By default, GSO is disabled for all ports.
testpmd> csum set tcp hw <port_id>
+ UDP GSO is the same as IP fragmentation, which treats the UDP header
+ as the payload and does not modify it during segmentation. That is,
+ after UDP GSO, only the first output fragment has the original UDP
+ header. Therefore, users need to enable HW IP checksum calculation
+ and SW UDP checksum calculation for GSO-enabled ports, if they want
+ correct checksums for UDP/IPv4 packets.
+
set gso segsz
~~~~~~~~~~~~~