[PATCH v2] examples/dma: support DMA dequeue when no packet received

[Thomas Monjalon]

25/07/2022 14:48, Bruce Richardson:
> On Mon, Jul 25, 2022 at 08:22:00PM +0800, Chengwen Feng wrote:
> > Currently the example using DMA in asynchronous mode, which are:
> > 	nb_rx = rte_eth_rx_burst();
> > 	if (nb_rx == 0)
> > 		continue;
> > 	...
> > 	dma_enqueue(); // enqueue the received packets copy request
> > 	nb_cpl = dma_dequeue(); // get copy completed packets
> > 	...
> > 
> > There are no waiting inside dma_dequeue(), and this is why it's called
> > asynchronus. If there are no packet received, it won't call
> > dma_dequeue(), but some packets may still in the DMA queue which
> > enqueued in last cycle. As a result, when the traffic is stopped, the
> > sent packets and received packets are unbalanced from the perspective
> > of the traffic generator.
> > 
> > The patch supports DMA dequeue when no packet received, it helps to
> > judge the test result by comparing the sent packets with the received
> > packets on traffic generator sides.
> > 
> > Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
> 
> Acked-by: Bruce Richardson <bruce.richardson at intel.com>
Acked-by: Kevin Laatz <kevin.laatz at intel.com>

Applied, thanks.