[dpdk-dev] [PATCH v2 6/7] examples/vhost: add an option to enable dequeue zero copy

Maxime Coquelin maxime.coquelin at redhat.com
Mon Sep 26 23:05:16 CEST 2016



On 09/23/2016 06:13 AM, Yuanhan Liu wrote:
> Add an option, --dequeue-zero-copy, to enable dequeue zero copy.
>
> One thing worth noting while using dequeue 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 dequeue 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.
>
> Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
> ---
>  examples/vhost/main.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
Thanks,
Maxime


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