From: Chengwen Feng fengchengwen@huawei.com
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 Acked-by: Bruce Richardson bruce.richardson@intel.com Acked-by: Kevin Laatz kevin.laatz@intel.com --- examples/dma/dmafwd.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/examples/dma/dmafwd.c b/examples/dma/dmafwd.c index 9b17b40dbf..b06042e5fe 100644 --- a/examples/dma/dmafwd.c +++ b/examples/dma/dmafwd.c @@ -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);