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authorEric Dumazet <eric.dumazet@gmail.com>2009-06-05 04:04:16 (GMT)
committerDavid S. Miller <davem@davemloft.net>2009-06-08 07:21:48 (GMT)
commit042a53a9e437feaf2230dd2cadcecfae9c7bfe05 (patch)
treeae9078f61e390a3014aecb3fe80d3438ab25ee51 /drivers/net/ixgb
parenteae3f29cc73f83cc3f1891d3ad40021b5172c630 (diff)
downloadlinux-042a53a9e437feaf2230dd2cadcecfae9c7bfe05.tar.xz
net: skb_shared_info optimization
skb_dma_unmap() is quite expensive for small packets, because we use two different cache lines from skb_shared_info. One to access nr_frags, one to access dma_maps[0] Instead of dma_maps being an array of MAX_SKB_FRAGS + 1 elements, let dma_head alone in a new dma_head field, close to nr_frags, to reduce cache lines misses. Tested on my dev machine (bnx2 & tg3 adapters), nice speedup ! Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ixgb')
-rw-r--r--drivers/net/ixgb/ixgb_main.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 6eb7f37..9c897cf 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1300,7 +1300,7 @@ ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
buffer_info->length = size;
WARN_ON(buffer_info->dma != 0);
buffer_info->time_stamp = jiffies;
- buffer_info->dma = map[0] + offset;
+ buffer_info->dma = skb_shinfo(skb)->dma_head + offset;
pci_map_single(adapter->pdev,
skb->data + offset,
size,
@@ -1340,7 +1340,7 @@ ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
buffer_info->length = size;
buffer_info->time_stamp = jiffies;
- buffer_info->dma = map[f + 1] + offset;
+ buffer_info->dma = map[f] + offset;
buffer_info->next_to_watch = 0;
len -= size;