I set the dataroom of the mbuf from 2048 to 64B. To receive large packets(>64B) with a 64B size dataroom mbuf, DPDK reminds me that I need to enable scattered mode. So how can I enable scattered mode?

I set the dataroom of the mbuf from 2048 to 64B. To receive large packets(>64B) with a 64B size dataroom mbuf, DPDK reminds me that I need to enable scattered mode. So how can I enable scattered mode?

Rx scatter can be enabled at the stage when rte_eth_dev_configure() is invoked. To do that, one should pass flag RTE_ETH_RX_OFFLOAD_SCATTER via dev_conf.rx_mode.offloads, with dev_conf being passed by pointer as the last argument to rte_eth_dev_configure().
To check the feature with testpmd, one can pass command-line argument --enable-scatter.