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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-06-05 04:04:16 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-06-08 00:21:48 -0700 |
| commit | 042a53a9e437feaf2230dd2cadcecfae9c7bfe05 (patch) | |
| tree | ae9078f61e390a3014aecb3fe80d3438ab25ee51 /drivers/net/e1000 | |
| parent | eae3f29cc73f83cc3f1891d3ad40021b5172c630 (diff) | |
| download | lwn-042a53a9e437feaf2230dd2cadcecfae9c7bfe05.tar.gz lwn-042a53a9e437feaf2230dd2cadcecfae9c7bfe05.zip | |
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/e1000')
| -rw-r--r-- | drivers/net/e1000/e1000_main.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index 05e87a59f1c6..8d36743c8140 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -2998,7 +2998,7 @@ static int e1000_tx_map(struct e1000_adapter *adapter, size -= 4; buffer_info->length = size; - buffer_info->dma = map[0] + offset; + buffer_info->dma = skb_shinfo(skb)->dma_head + offset; buffer_info->time_stamp = jiffies; buffer_info->next_to_watch = i; @@ -3039,7 +3039,7 @@ static int e1000_tx_map(struct e1000_adapter *adapter, size -= 4; buffer_info->length = size; - buffer_info->dma = map[f + 1] + offset; + buffer_info->dma = map[f] + offset; buffer_info->time_stamp = jiffies; buffer_info->next_to_watch = i; |