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authorJunchang Wang <junchangwang@gmail.com>2010-12-08 11:55:16 -0500
committerDavid S. Miller <davem@davemloft.net>2010-12-10 18:36:52 -0500
commita8d764b9832d3cc86019f71916665dd2d337d7c2 (patch)
tree08637ac7b04a569b1b5152f8e52434c9f284bf29 /net/core/pktgen.c
parent4afb7527ac8cc7bd8f03570e12f6eed0eca03363 (diff)
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>
Diffstat (limited to 'net/core/pktgen.c')
-rw-r--r--net/core/pktgen.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 2953b2abc971..18fe20dacc60 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,
2660 sprintf(pkt_dev->result, "No memory"); 2660 sprintf(pkt_dev->result, "No memory");
2661 return NULL; 2661 return NULL;
2662 } 2662 }
2663 prefetchw(skb->data);
2663 2664
2664 skb_reserve(skb, datalen); 2665 skb_reserve(skb, datalen);
2665 2666
@@ -3007,6 +3008,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev,
3007 sprintf(pkt_dev->result, "No memory"); 3008 sprintf(pkt_dev->result, "No memory");
3008 return NULL; 3009 return NULL;
3009 } 3010 }
3011 prefetchw(skb->data);
3010 3012
3011 skb_reserve(skb, 16); 3013 skb_reserve(skb, 16);
3012 3014