[dpdk-dev] [PATCH v6 0/3] Support TCP/IPv4 GRO in DPDK

[Tan, Jianfeng]

On 6/23/2017 10:43 PM, Jiayu Hu wrote:
> Generic Receive Offload (GRO) is a widely used SW-based offloading
> technique to reduce per-packet processing overhead. It gains performance
> by reassembling small packets into large ones. Therefore, we propose to
> support GRO in DPDK.
>
> To enable more flexibility to applications, DPDK GRO is implemented as
> a user library. Applications explicitly use the GRO library to merge
> small packets into large ones. DPDK GRO provides two reassembly modes:
> lightweigth mode and heavyweight mode. If applications want to merge
> packets in a simple way, they can select lightweight mode API. If
> applications need more fine-grained controls, they can select heavyweigth
> mode API.
>
> This patchset is to support TCP/IPv4 GRO in DPDK. The first patch is to
> provide a GRO API framework. The second patch is to support TCP/IPv4 GRO.
> The last patch is to enable TCP/IPv4 GRO in testpmd.
>
> We perform many iperf tests to see the performance gains from DPDK GRO.
>
> The test environment is:
> a. two 25Gbps physical ports (p0 and p1) are linked together. Assign p0
> 	to one networking namespace and assign p1 to DPDK;
> b. enable TSO for p0. Run iperf client on p0;
> c. launch testpmd with p1 and a vhost-user port, and run it in csum
> 	forwarding mode. Select TCP HW checksum calculation for the
> 	vhost-user port in csum forwarding engine. And for better
> 	performance, we select IPv4 and TCP HW checksum calculation for p1
> 	too;
> d. launch a VM with one CPU core and a virtio-net port. The VM OS is
> 	ubuntu 16.04 whose virtio-net driver supports GRO. Enables RX csum
> 	offloading and mrg_rxbuf for the VM. Iperf server runs in the VM;
> e. to run iperf tests, we need to avoid the csum forwarding engine
> 	compulsorily changes packet mac addresses. SO in our tests, we
> 	comment these codes out (line701 ~ line704 in csumonly.c).
>
> In each test, we run iperf with the following three configurations:
> 	- single flow and single TCP stream
> 	- multiple flows and single TCP stream
> 	- single flow and parallel TCP streams

To  me, flow == TCP stream; so could you explain what does flow mean?

>
> We run above iperf tests on three scenatios:
> 	s1: disabling kernel GRO and enabling DPDK GRO
> 	s2: disabling kernel GRO and disabling DPDK GRO
> 	s3: enabling kernel GRO and disabling DPDK GRO
> Comparing the throughput of s1 with s2, we can see the performance gains
> from DPDK GRO. Comparing the throughput of s1 and s3, we can compare DPDK
> GRO performance with kernel GRO performance.
>
> Test results:
> 	- DPDK GRO throughput is almost 2 times than the throughput of no
> 		DPDK GRO and no kernel GRO;
> 	- DPDK GRO throughput is almost 1.2 times than the throughput of
> 		kernel GRO.
>
> Change log
> ==========
> v6:
> - avoid checksum validation and calculation
> - enable to process IP fragmented packets
> - add a command in testpmd
> - update documents
> - modify rte_gro_timeout_flush and rte_gro_reassemble_burst
> - rename veriable name
> v5:
> - fix some bugs
> - fix coding style issues
> v4:
> - implement DPDK GRO as an application-used library
> - introduce lightweight and heavyweight working modes to enable
> 	fine-grained controls to applications
> - replace cuckoo hash tables with simpler table structure
> v3:
> - fix compilation issues.
> v2:
> - provide generic reassembly function;
> - implement GRO as a device ability:
> add APIs for devices to support GRO;
> add APIs for applications to enable/disable GRO;
> - update testpmd example.
>
> Jiayu Hu (3):
>    lib: add Generic Receive Offload API framework
>    lib/gro: add TCP/IPv4 GRO support
>    app/testpmd: enable TCP/IPv4 GRO
>
>   app/test-pmd/cmdline.c                      | 125 +++++++++
>   app/test-pmd/config.c                       |  37 +++
>   app/test-pmd/csumonly.c                     |   5 +
>   app/test-pmd/testpmd.c                      |   3 +
>   app/test-pmd/testpmd.h                      |  11 +
>   config/common_base                          |   5 +
>   doc/guides/rel_notes/release_17_08.rst      |   7 +
>   doc/guides/testpmd_app_ug/testpmd_funcs.rst |  34 +++
>   lib/Makefile                                |   2 +
>   lib/librte_gro/Makefile                     |  51 ++++
>   lib/librte_gro/rte_gro.c                    | 221 ++++++++++++++++
>   lib/librte_gro/rte_gro.h                    | 195 ++++++++++++++
>   lib/librte_gro/rte_gro_tcp.c                | 393 ++++++++++++++++++++++++++++
>   lib/librte_gro/rte_gro_tcp.h                | 188 +++++++++++++
>   lib/librte_gro/rte_gro_version.map          |  12 +
>   mk/rte.app.mk                               |   1 +
>   16 files changed, 1290 insertions(+)
>   create mode 100644 lib/librte_gro/Makefile
>   create mode 100644 lib/librte_gro/rte_gro.c
>   create mode 100644 lib/librte_gro/rte_gro.h
>   create mode 100644 lib/librte_gro/rte_gro_tcp.c
>   create mode 100644 lib/librte_gro/rte_gro_tcp.h
>   create mode 100644 lib/librte_gro/rte_gro_version.map
>