Re: [PATCH] examples/dma: support DMA dequeue when no packet received

[fengchengwen <fengchengwen@huawei.com>]

On 2022/7/25 18:01, Bruce Richardson wrote:
> On Mon, Jul 25, 2022 at 04:12:12PM +0800, Chengwen Feng wrote:

...

>> -		if (nb_rx == 0)
>> +		if (nb_rx == 0 && copy_mode != COPY_MODE_DMA_NUM)
>>  			continue;
>>  
>>  		port_statistics.rx[rx_config->rxtx_port] += nb_rx;
> 
> With this change, we would work through the all the receive packet
> processing code, and calling all it's functions, just witha packet count of
> zero. I therefore wonder if it would be cleaner to do the dma_dequeue
> immediately here on receiving zero, and then jumping to handle those
> dequeued packets. Something like the diff below.
> 
> /Bruce

Hi Bruce,

  Thank your review, already fix in V2.

> 
> @@ -408,8 +408,13 @@ dma_rx_port(struct rxtx_port_config *rx_config)
>                 nb_rx = rte_eth_rx_burst(rx_config->rxtx_port, i,
>                         pkts_burst, MAX_PKT_BURST);
>  
> -               if (nb_rx == 0)
> +               if (nb_rx == 0) {
> +                       if (copy_mode == COPY_MODE_DMA_NUM &&
> +                                       (nb_rx = dma_dequeue(pkts_burst, pkts_burst_copy,
> +                                               MAX_PKT_BURST, rx_config->dmadev_ids[i])) > 0)
> +                               goto handle_tx;
>                         continue;
> +               }
>  
>                 port_statistics.rx[rx_config->rxtx_port] += nb_rx;
>  
> @@ -450,6 +455,7 @@ dma_rx_port(struct rxtx_port_config *rx_config)
>                                         pkts_burst_copy[j]);
>                 }
>  
> +handle_tx:
>                 rte_mempool_put_bulk(dma_pktmbuf_pool,
>                         (void *)pkts_burst, nb_rx);
> 
> 
> .
>