[ovs-dev] [PATCH] dpif-netdev: move header prefetch earlier into the receive function
Zoltan Kiss
zoltan.kiss at linaro.org
Thu Sep 17 20:29:45 UTC 2015
It's better to have it in the cache as soon as possible. On my test setup it
meant a 0.7 Mpps increase.
Signed-off-by: Zoltan Kiss <zoltan.kiss at linaro.org>
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 72e5653..3312cc0 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -3229,11 +3229,6 @@ emc_processing(struct dp_netdev_pmd_thread *pmd, struct dp_packet **packets,
continue;
}
- if (i != cnt - 1) {
- /* Prefetch next packet data */
- OVS_PREFETCH(dp_packet_data(packets[i+1]));
- }
-
miniflow_extract(packets[i], &key.mf);
key.len = 0; /* Not computed yet. */
key.hash = dpif_netdev_packet_get_rss_hash(packets[i], &key.mf);
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index e4e3d2c..c3c7ec0 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -1015,7 +1015,7 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_, struct dp_packet **packets,
struct netdev_rxq_dpdk *rx = netdev_rxq_dpdk_cast(rxq_);
struct netdev *netdev = rx->up.netdev;
struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
- int nb_rx;
+ int nb_rx, i;
/* There is only one tx queue for this core. Do not flush other
* queues.
@@ -1033,6 +1033,9 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_, struct dp_packet **packets,
return EAGAIN;
}
+ for (i = 0; i < nb_rx; i++)
+ OVS_PREFETCH(dp_packet_data(packets[i]));
+
*c = nb_rx;
return 0;
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