Performance of CX7 with 'eth' pattern versus 'eth/ipv4' in hairpin

[Bing Zhao]

Hi Tony,

Could you also try to test with:
1. QUEUE action instead of RSS and check 1 queue performance.
2. when trying to test IPv4 only case, try the following 3 commands with this order -
	flow create 0 ingress group 0 pattern end actions jump group 1 / end
	flow create 0 ingress group 1 pattern priority 1 eth / ipv6 / end actions count / rss queues 6 7 8 9 end / end
	flow create 0 ingress group 1 pattern priority 1 eth / ipv4 / end actions count / rss queues 6 7 8 9 end / end

BR. Bing

> -----Original Message-----
> From: Tony Hart <tony.hart at domainhart.com>
> Sent: Wednesday, June 26, 2024 7:39 PM
> To: users at dpdk.org
> Subject: Performance of CX7 with 'eth' pattern versus 'eth/ipv4' in hairpin
> 
> External email: Use caution opening links or attachments
> 
> 
> I'm using a CX7 and testing hairpin queues.  The test traffic is entirely
> IPv4+UDP with distributed SIP,DIP pairs and received packets are u-turned via
> hairpin in the CX7 (single 400G interface).
> 
> I see different performance when I use a pattern of 'eth' versus 'eth/ipv4' in
> the hairpin flow entry.  From testing it seems that specifying just 'eth' is
> sufficient to invoke RSS and 'eth/ipv4'
> should be equivalent since the traffic is all ipv4, but I'm getting ~104Gbps for
> the 'eth' pattern and  ~124Gbps for 'eth/ipv4' pattern.
> 
> Any thoughts on why there is such a performance difference here?
> 
> thanks
> tony
> 
> This is the 'eth' pattern testpmd commands flow create 0 ingress group 0
> pattern end actions jump group 1 / end flow create 0 ingress group 1 pattern
> eth / end actions count / rss queues 6 7 8 9 end / end
> 
> The testpmd commands for 'eth/ipv4'
> flow create 0 ingress group 0 pattern end actions jump group 1 / end flow
> create 0 ingress group 1 pattern eth / ipv4 / end actions count / rss queues 6 7
> 8 9 end / end
> 
> 
> This is the testpmd command line...
> dpdk-testpmd -l8-14 -a81:00.0,dv_flow_en=1 -- -i --nb-cores 6 --rxq 6 --txq 6
> --port-topology loop --forward-mode=rxonly --hairpinq 4 --hairpin-mode
> 0x10
> 
> Versions
> mlnx-ofa_kernel-24.04-OFED.24.04.0.6.6.1.rhel9u4.x86_64
> kmod-mlnx-ofa_kernel-24.04-OFED.24.04.0.6.6.1.rhel9u4.x86_64
> mlnx-ofa_kernel-devel-24.04-OFED.24.04.0.6.6.1.rhel9u4.x86_64
> ofed-scripts-24.04-OFED.24.04.0.6.6.x86_64
> 
> DPDK: v24.03