[dpdk-users] DPDK Enqueue Pipeline

[Stephen Hemminger]

On Wed, 26 Feb 2020 16:08:17 +0530
"Avinash ." <avinash.182cs009 at nitk.edu.in> wrote:

> Hi all,
> The DPDK QoS scheduler has a 4-stage pipeline for enqueuing the packets.
> This is used for hiding the latency of prefetching the data structures.
> Why is there no pipeline for dequeuing the packets?
> How does the dequeue function maintain the state of a packet? In other
> words, if I want to backtrace the packet that is dequeued to get the info
> of what was the traffic class and from which queue the packet was dequeued.
> Is there any way to get this.
> 
> Thanks,
> Avinash.

Prefetching after receive burst is the responsibility of the application.
You can't prefetch until the data arrives, and the amount and policy
for prefetch depends on the timing of the application.

There simple examples in DPDK and more complex in how FD.io VPP does it.