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Subject: Re: [PATCH v2] examples/dma: support DMA dequeue when no packet
 received
From: fengchengwen <fengchengwen@huawei.com>
To: <thomas@monjalon.net>
CC: <dev@dpdk.org>, <kevin.laatz@intel.com>, <bruce.richardson@intel.com>
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Date: Tue, 13 Sep 2022 09:44:18 +0800
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Kindly ping.

On 2022/7/25 20:22, 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@huawei.com>
> ---

...