Re: [PATCH] vhost: make vhost lockless enqueue configurable

[Panu Matilainen <pmatilai-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 04/29/2015 02:29 PM, Huawei Xie wrote:
> vhost enabled vSwitch could have their own thread-safe vring enqueue policy.
> Add the RTE_LIBRTE_VHOST_LOCKLESS_ENQ macro for vhost lockless enqueue.
> Turn it off by default.
>
> Signed-off-by: Huawei Xie <huawei.xie-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
>   config/common_linuxapp        |  1 +
>   lib/librte_vhost/vhost_rxtx.c | 24 +++++++++++++++++++++++-
>   2 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/config/common_linuxapp b/config/common_linuxapp
> index 0078dc9..7f59499 100644
> --- a/config/common_linuxapp
> +++ b/config/common_linuxapp
> @@ -421,6 +421,7 @@ CONFIG_RTE_KNI_VHOST_DEBUG_TX=n
>   #
>   CONFIG_RTE_LIBRTE_VHOST=n
>   CONFIG_RTE_LIBRTE_VHOST_USER=y
> +CONFIG_RTE_LIBRTE_VHOST_LOCKLESS_ENQ=n
>   CONFIG_RTE_LIBRTE_VHOST_DEBUG=n
>
>   #
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 510ffe8..475be6e 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -80,7 +80,11 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>   	 * they need to be reserved.
>   	 */
>   	do {
> +#ifdef RTE_LIBRTE_VHOST_LOCKESS_ENQ
>   		res_base_idx = vq->last_used_idx_res;
> +#else
> +		res_base_idx = vq->last_used_idx;
> +#endif

These things should be runtime configurable, not build options. Please 
do not assume everybody builds DPDK separately for each and every 
application that might ever be.

	- Panu -