Re: [dpdk-dev] [PATCH v2 3/4] vhost: allocate and free packets in bulk

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 4/7/21 12:17 PM, Balazs Nemeth wrote:
> Now that all allocation and freeing has been moved together, use the
> faster bulk versions instead of handling packets one by one.
> 
> Signed-off-by: Balazs Nemeth <bnemeth@redhat.com>
> ---
>  lib/librte_vhost/virtio_net.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 496f750e3..2f0c97b91 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -2469,10 +2469,10 @@ virtio_dev_tx_packed(struct virtio_net *dev,
>  {
>  	uint32_t pkt_idx = 0;
>  	uint32_t remained = count;
> -	uint16_t i;
>  
> -	for (i = 0; i < count; ++i)
> -		pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
> +	if (rte_pktmbuf_alloc_bulk(mbuf_pool, pkts, count)) {
> +		return 0;
> +	}

OK, get it now :)
Maybe just add a comment in previous patches that it is going to be
handled when moving to bulk allocation.

>  
>  	do {
>  		rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
> @@ -2497,8 +2497,9 @@ virtio_dev_tx_packed(struct virtio_net *dev,
>  
>  	} while (remained);
>  
> -	for (i = pkt_idx; i < count; ++i)
> -		rte_pktmbuf_free(pkts[i]);
> +	if (pkt_idx != count) {
> +		rte_pktmbuf_free_bulk(&pkts[pkt_idx], count - pkt_idx);
> +	}
>  
>  	if (vq->shadow_used_idx) {
>  		do_data_copy_dequeue(vq);
>