[dpdk-dev] [RFC] ethdev: rte_eth_rx_burst() requirements fornb_pkts

[Bruce Richardson]

On Fri, Aug 28, 2020 at 11:03:59AM +0200, Morten Brørup wrote:
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Bruce Richardson
> >
<snip>
> > 
> > Right. For now then, it seems like just documenting a minimum burst
> > size is
> > reasonable.
> 
> I agree. It is so far from the spirit of DPDK to call rte_eth_rx_burst() with a small nb_pkts that the driver developers didn't even consider it. The API documentation needs fixing, not the drivers.
> 
> It doesn't take care of your example 4 packet latency sensitive application, though. Which BTW also doesn’t work today on drivers with vector support. So it might not be a real world scenario anyway. :-)
> 
AFAIK, 8 is the smallest burst guaranteed to work everywhere, but I think
just about everything bar the AVX2 i40e code path also supports 4 as a
burst size. Therefore adjusting to 4 as min-burst might well be reasonable.

/Bruce