[dpdk-dev] [PATCH 6/6] examples/vhost: add an option to enable Tx zero copy

[Thomas Monjalon]

2016-08-23 16:10, Yuanhan Liu:
> One thing worth noting while using Tx zero copy is the nb_tx_desc has
> to be small enough so that the eth driver will hit the mbuf free
> threshold easily and thus free mbuf more frequently.
> 
> The reason behind that is, when Tx zero copy is enabled, guest Tx used
> vring will be updated only when corresponding mbuf is freed. If mbuf is
> not freed frequently, the guest Tx vring could be starved.

I think you should explain this behaviour in the doc of the vhost flag.