[dpdk-dev] [PATCH v11 0/3] Support TCP/IPv4 GRO in DPDK

[Jiayu Hu <jiayu.hu@intel.com>]

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:
lightweight mode and heavyweight mode. If applications want to merge
packets in a simple way and the number of packets is small, they can
select the lightweight mode API. If applications need more fine-grained
controls, they can select the heavyweight 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 client thread 
	- multiple flows and single TCP client thread
	- single flow and parallel TCP client threads

We run above iperf tests on three scenarios:
	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
==========
v11:
- avoid converting big-endian to little-endian when compare key
- add sent_seq and ip_id to gro_tcp4_item to accelarate packet
	reassembly
- remove max_packet_size from rte_gro_param
- add inline functions to replace reduplicate codes
- change external API names and structure name
	(rte_gro_tbl_xxx -> rte_gro_ctx_xxx)
- fix coding style issues and order issue in rte_gro_version.map
- change inacccurate comments
- change internal files name from rte_gro_tcp4.x to gro_tcp4.x
v10:
- add support to merge '<seq=2, seq=1>' TCP/IPv4 packets
- check if IP ID is consecutive and update IP ID for merged packets
- check SYN, FIN, PSH, RST, URG flags
- use different reassembly table structures and APIs for TCP/IPv4 GRO
	and TCP/IPv6 GRO
- change file name from 'rte_gro_tcp.x' to 'rte_gro_tcp4.x'
v9:
- avoid defining variable size structure array and memset variable size
	in rte_gro_reassemble_burst
- change internal structure name from 'te_gro_tbl' to 'gro_tbl'
- delete useless variables in rte_gro_tcp.c
v8:
- merge rte_gro_flush and rte_gro_timeout_flush together and optimize
	flushing operation
- enable rte_gro_reassemble to process N inputted packets
- add rte_gro_tbl_item_num to get packet num in the GRO table
- add 'lastseg' to struct gro_tcp_item to get last segment faster
- add operations to handle rte_malloc failure
- use mbuf->l2_len/l3_len/l4_len instead of parsing header
- remove 'is_groed' and 'is_valid' in struct gro_tcp_item
- fix bugs in gro_tcp4_reassemble
- pass start-time as a parameter to avoid frequently calling rte_rdtsc 
- modify rte_gro_tbl_create prototype
- add 'RTE_' to external macros
- remove 'goto'
- remove inappropriate 'const'
- hide internal variables
v7:
- add a macro 'GRO_MAX_BURST_ITEM_NUM' to avoid stack overflow in
	rte_gro_reassemble_burst
- change macro name (_NB to _NUM)
- add '#ifdef __cplusplus ...' in rte_gro.h
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                       |  36 ++
 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/gro_tcp4.c                   | 493 ++++++++++++++++++++++++++++
 lib/librte_gro/gro_tcp4.h                   | 206 ++++++++++++
 lib/librte_gro/rte_gro.c                    | 266 +++++++++++++++
 lib/librte_gro/rte_gro.h                    | 198 +++++++++++
 lib/librte_gro/rte_gro_version.map          |  12 +
 mk/rte.app.mk                               |   1 +
 16 files changed, 1455 insertions(+)
 create mode 100644 lib/librte_gro/Makefile
 create mode 100644 lib/librte_gro/gro_tcp4.c
 create mode 100644 lib/librte_gro/gro_tcp4.h
 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_version.map

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