Accelerated networking with dpdk performance issue

Question

I am running a D8sV3 type instance on azure with RHEL7.9 & accelerated networking enabled on one of the interface.

On this am running my DPDK app which is binding to the VF exposed & its corresponding netvsc interface via vdev_netvsc driver as suggested in https://learn.microsoft.com/en-us/azure/virtual-network/setup-dpdk

DPDK doc : vdev_netvsc.html

The expected behavior is that all traffic should flow through the physical interface (VF) and not from synthetic device (eth2 in my case).
But I can see all traffic coming to eth2 & dtap0 devices. This is causing my dpdk cpus to handle RX interrupts for these packets causing major performance issues & jitters. I am not understanding why all these packets are being mirrored to slow path.

Note: All my traffic is UDP.

I would like to know if there is any setting am missing here. This is causing a lot of problems for me to qualify on Azure cloud with expected throughput.

Thanks.

Answer 1

Hi,

Thank you for posting your query.

Kindly follow the steps provided below to resolve your issue.

Data Plane Development Kit (DPDK) on Azure offers a faster user-space packet processing framework for performance-intensive applications. This framework bypasses the virtual machine’s kernel network stack.

In typical packet processing that uses the kernel network stack, the process is interrupt-driven. When the network interface receives incoming packets, there is a kernel interrupt to process the packet and a context switch from the kernel space to the user space. DPDK eliminates context switching and the interrupt-driven method in favor of a user-space implementation that uses poll mode drivers for fast packet processing.

Go to this link for your reference and other troubleshooting procedures https://learn.microsoft.com/en-us/azure/virtual-network/setup-dpdk

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