[dpdk-dev] rte_prefetch0() is effective?

[Moon-Sang Lee]

I see codes as below in example directory, and I wonder it is effective.
Coherent IO is adopted to modern architectures,
so I think that DMA initiation by rte_eth_rx_burst() might already fulfills
cache lines of RX buffers.
Do I really need to call rte_prefetchX()?

            nb_rx = rte_eth_rx_burst(portid, queueid, pkts_burst,
MAX_PKT_BURST);
            ...
            /* Prefetch and forward already prefetched packets */
            for (j = 0; j < (nb_rx - PREFETCH_OFFSET); j++) {
                rte_prefetch0(rte_pktmbuf_mtod(pkts_burst[
                        j + PREFETCH_OFFSET], void *));
                l3fwd_simple_forward(pkts_burst[j], portid,
                    qconf);
            }


-- 
Moon-Sang Lee, SW Engineer
Email: sang0627 at gmail.com
Wisdom begins in wonder. *Socrates*