VRouter Performance Parameters:

Segmentation in Software :

Segmentation in Software is modifing the MSS of TCP packets by considering the OVERLAY HEADER. This MSS updation helps to avoid the fragmentation and increase the throughput.

GRO (Generic Receive Offload) /RPS (Receive Packet Steering):

Generic Receive Offload is buffering couple of packets and interrupt(send) it to CPU at one shot. It helps to increase the CPU availability and increase the thruput.

RPS is helps to offloading the packet handling to multiple CPUs.

In 3.2, By Default, Segmentation in Software and GRO is enabled.

Vrouter running information:

cloud@contraildev:~$ sudo vrouter --info
vRouter module version       3.2.3.3 (Built by root@contraildev on 2017-09-03 16:09:08.032456)

Startup parameters
    Interfaces limit                     4352
    VRF tables limit                     4096
    NextHops limit                       65536
    MPLS Labels limit                    5120
    Bridge Table limit                   128
    Bridge Table Overflow limit          1024
    Flow Table limit                     4096
    Flow Table overflow limit            512
    Mirror entries limit                 255

Runtime parameters
  Performance tweaks
    GRO                                  1
    Segmentation in software             1
  TCP MSS adjust settings
    TCP MSS on packets from VM           1
    TCP MSS on packet sent to VM         1
  RPS settings
    RPS after pulling inner hdr (perfr1) 0
    RPS after GRO on pkt1 (perfr2)       1
    RPS from phys rx handler (perfr3)    1
    Pull inner header (faster version)   1
    CPU to send pkts to, if perfr1 set   0
    CPU to send pkts to, if perfr2 set   0
    CPU to send pkts to, if perfr3 set   0
  Other settings
    NIC cksum offload for outer UDP hdr  0
    Flow hold limit:                     8192
    MPLS over UDP globally               0
    Used Flow entries                    4
    Used Over Flow entries               0
    Used Bridge entries                  16
    Used Over Flow bridge entries        0

cloud@contraildev:~$

How to Enable /Disable the Segmentation/GRO:

Note : This configuration can be chaged in runtime. No need to reload the Vrouter module.

To Disable the GRO:

sudo vrouter --perfr 0

To Enable the GRO

sudo vrouter --perfr 1

To Disable the Segmentaion in sofware :

sudo vrouter --perfs 0

To Enable the Segmentaion in sofware :

sudo vrouter --perfs 1