[dpdk-dev] [PATCH v2 0/5] maximize vector rx burst for PMDs

[Morten Brørup]

> From: Jeff Guo [mailto:jia.guo at intel.com]
> Sent: Thursday, August 27, 2020 12:10 PM
> 
> The limitation of burst size in vector rx was removed, since it should
> retrieve as much received packets as possible. And also the scattered
> receive path should use a wrapper function to achieve the goal of
> burst maximizing.
> 
> This patch set aims to maximize vector rx burst for for
> ixgbe/i40e/ice/iavf/fm10k PMDs.
> 
> v2->v1:
> 1:add fm10k driver case
> 2:refine some doc
> 

I now noticed that the vector functions also does:
nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_I40E_DESCS_PER_LOOP);

I am not sure about this, but if I read it correctly, calling rte_eth_rx_burst() with nb_pkts = 33 (not 32) would only return 32 packets, even if more packets are available. (I assume that RTE_I40E_DESCS_PER_LOOP is 32.) In this case, I guess that you need to read the remaining of the requested packets using the non-vector function in order to support any nb_pkts value.

That is, unless the rte_eth_rx_burst() API is extended with requirements to nb_pkts, as discussed in the other thread:
http://inbox.dpdk.org/dev/20200827114117.GD569@bricha3-MOBL.ger.corp.intel.com/T/#mc8051e9022d6aeb20c51c5a226b2274d3d6d4266


Med venlig hilsen / kind regards
- Morten Brørup