From a8d764b9832d3cc86019f71916665dd2d337d7c2 Mon Sep 17 00:00:00 2001 From: Junchang Wang <junchangwang@gmail.com> Date: Wed, 8 Dec 2010 16:55:16 +0000 Subject: pktgen: adding prefetchw() call We know for sure pktgen is going to write skb->data right after *_alloc_skb, causing unnecessary cache misses. Idea is to add a prefetchw() call to prefetch the first cache line indicated by skb->data. On systems with Adjacent Cache Line Prefetch, it's probably two cache lines are prefetched. With this patch, pktgen on Intel SR1625 server with two E5530 quad-core processors and a single ixgbe-based NIC went from 8.63Mpps to 9.03Mpps, with 4.6% improvement. Signed-off-by: Junchang Wang <junchangwang@gmail.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/core/pktgen.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 2953b2abc97..18fe20dacc6 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2660,6 +2660,7 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev, sprintf(pkt_dev->result, "No memory"); return NULL; } + prefetchw(skb->data); skb_reserve(skb, datalen); @@ -3007,6 +3008,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev, sprintf(pkt_dev->result, "No memory"); return NULL; } + prefetchw(skb->data); skb_reserve(skb, 16); -- cgit v1.2.3