Re: [PATCH v10 0/6] Support TCP/IPv4, VxLAN, and GRE GSO in DPDK

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/7/2017 3:56 PM, Jiayu Hu wrote:
> Generic Segmentation Offload (GSO) is a SW technique to split large
> packets into small ones. Akin to TSO, GSO enables applications to
> operate on large packets, thus reducing per-packet processing overhead.
> 
> To enable more flexibility to applications, DPDK GSO is implemented
> as a standalone library. Applications explicitly use the GSO library
> to segment packets. This patch adds GSO support to DPDK for specific
> packet types: specifically, TCP/IPv4, VxLAN, and GRE.
> 
> The first patch introduces the GSO API framework. The second patch
> adds GSO support for TCP/IPv4 packets (containing an optional VLAN
> tag). The third patch adds GSO support for VxLAN packets that contain
> outer IPv4, and inner TCP/IPv4 headers (plus optional inner and/or 
> outer VLAN tags). The fourth patch adds GSO support for GRE packets
> that contain outer IPv4, and inner TCP/IPv4 headers (with optional 
> outer VLAN tag). The fifth patch in the series enables TCP/IPv4, VxLAN,
> and GRE GSO in testpmd's checksum forwarding engine. The final patch
> in the series adds GSO documentation to the programmer's guide.
> 
> Note that this patch set has dependency on the patch "app/testpmd: enable
> the heavyweight mode TCP/IPv4 GRO".
> http://dpdk.org/dev/patchwork/patch/29867/
> 
> Performance Testing
> ===================
> The performance of TCP/IPv4 GSO on a 10Gbps link is demonstrated using
> iperf. Setup for the test is described as follows:
> 
> a. Connect 2 x 10Gbps physical ports (P0, P1), which are in the same
>    machine, together physically.
> b. Launch testpmd with P0 and a vhost-user port, and use csum
>    forwarding engine with "retry".
> c. Select IP and TCP HW checksum calculation for P0; select TCP HW
>    checksum calculation for vhost-user port.
> d. Launch a VM with csum and tso offloading enabled.
> e. Run iperf-client on virtio-net port in the VM to send TCP packets.
>    With enabling csum and tso, the VM can send large TCP/IPv4 packets
>    (mss is up to 64KB).
> f. P1 is assigned to linux kernel and enabled kernel GRO. Run
>    iperf-server on P1.
> 
> We conduct three iperf tests:
> 
> test-1: enable GSO for P0 in testpmd, and set max GSO segment length
>     to 1514B. Run four iperf-client in the VM.
> test-2: enable TSO for P0 in testpmd, and set TSO segsz to 1514B. Run
>     four iperf-client in the VM.
> test-3: disable GSO and TSO in testpmd. Run two iperf-client in the VM.
> 
> Throughput of the above three tests:
> 
> test-1: 9Gbps
> test-2: 9.5Gbps
> test-3: 3Mbps
> 
> Functional Testing
> ==================
> Unlike TCP packets, VMs can't send large VxLAN or GRE packets. The max
> length of tunneled packets from VMs is 1514B. So current experiment
> method can't be used to measure VxLAN and GRE GSO performance, but simply
> test the functionality via setting small GSO segment length (e.g. 500B).
> 
> VxLAN
> -----
> To test VxLAN GSO functionality, we use the following setup:
> 
> a. Connect 2 x 10Gbps physical ports (P0, P1), which are in the same
>    machine, together physically.
> b. Launch testpmd with P0 and a vhost-user port, and use csum forwarding
>    engine with "retry".
> c. Testpmd commands:
>     - csum parse_tunnel on "P0"
>     - csum parse_tunnel on "vhost-user port"
>     - csum set outer-ip hw "P0"
>     - csum set ip hw "P0"
>     - csum set tcp hw "P0"
>     - csum set tcp hw "vhost-user port"
>     - set port "P0" gso on
>     - set gso segsz 500
> d. Launch a VM with csum and tso offloading enabled.
> e. Create a vxlan port for the virtio-net port in the VM. Run iperf-client
>    on the VxLAN port, so TCP packets are VxLAN encapsulated. However, the
>    max packet length is 1514B.
> f. P1 is assigned to linux kernel and kernel GRO is disabled. Similarly,
>    create a VxLAN port for P1, and run iperf-server on the VxLAN port.
> 
> In testpmd, we can see the length of all packets sent from P0 is smaller
> than or equal to 500B. Additionally, the packets arriving in P1 is
> encapsulated and is smaller than or equal to 500B.
> 
> GRE
> ---
> The same process may be used to test GRE functionality, with the exception that
> the tunnel type created for both the guest's virtio-net, and the host's kernel
> interfaces is GRE:
>    `ip tunnel add <gre tunnel> mode gre remote <remote IP> local <local_ip>`
> 
> As in the VxLAN testcase, the length of packets sent from P0, and received on
> P1, is less than 500B.
> 

<...>

> Jiayu Hu (3):
>   gso: add Generic Segmentation Offload API framework
>   gso: add TCP/IPv4 GSO support
>   app/testpmd: enable TCP/IPv4, VxLAN and GRE GSO
> 
> Mark Kavanagh (3):
>   gso: add VxLAN GSO support
>   gso: add GRE GSO support
>   doc: add GSO programmer's guide

Series applied to dpdk-next-net/master, thanks.