[dpdk-dev] [Patch v2] Eth driver optimization: Prefetch variable structure
Polehn, Mike A
mike.a.polehn at intel.com
Tue Nov 3 16:00:15 CET 2015
Adds Eth driver prefetch variable structure to CPU cache 0 while calling into tx or rx
device driver operation.
RFC 2544 test of NIC task test measurement points show improvement of lower
latency and/or better packet throughput indicating clock cycles saved.
Signed-off-by: Mike A. Polehn <mike.a.polehn at intel.com>
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 8a8c82b..09f1069 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2357,11 +2357,15 @@ rte_eth_rx_burst(uint8_t port_id, uint16_t queue_id,
struct rte_mbuf **rx_pkts, const uint16_t nb_pkts)
{
struct rte_eth_dev *dev;
+ void *rxq;
dev = &rte_eth_devices[port_id];
- int16_t nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
- rx_pkts, nb_pkts);
+ /* rxq is going to be immediately used, prefetch it */
+ rxq = dev->data->rx_queues[queue_id];
+ rte_prefetch0(rxq);
+
+ int16_t nb_rx = (*dev->rx_pkt_burst)(rxq, rx_pkts, nb_pkts);
#ifdef RTE_ETHDEV_RXTX_CALLBACKS
struct rte_eth_rxtx_callback *cb = dev->post_rx_burst_cbs[queue_id];
@@ -2499,6 +2503,7 @@ rte_eth_tx_burst(uint8_t port_id, uint16_t queue_id,
struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
{
struct rte_eth_dev *dev;
+ void *txq;
dev = &rte_eth_devices[port_id];
@@ -2514,7 +2519,11 @@ rte_eth_tx_burst(uint8_t port_id, uint16_t queue_id,
}
#endif
- return (*dev->tx_pkt_burst)(dev->data->tx_queues[queue_id], tx_pkts, nb_pkts);
+ /* txq is going to be immediately used, prefetch it */
+ txq = dev->data->tx_queues[queue_id];
+ rte_prefetch0(txq);
+
+ return (*dev->tx_pkt_burst)(txq, tx_pkts, nb_pkts);
}
#endif
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