diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-06-05 06:04:16 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-06-08 09:21:48 +0200 |
| commit | 042a53a9e437feaf2230dd2cadcecfae9c7bfe05 (patch) | |
| tree | ae9078f61e390a3014aecb3fe80d3438ab25ee51 /drivers/net/e1000e | |
| parent | net: num_dma_maps is not used (diff) | |
| download | linux-042a53a9e437feaf2230dd2cadcecfae9c7bfe05.tar.xz linux-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/e1000e')
| -rw-r--r-- | drivers/net/e1000e/netdev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c index 38694c79edcc..9043f1b845fe 100644 --- a/drivers/net/e1000e/netdev.c +++ b/drivers/net/e1000e/netdev.c @@ -3916,7 +3916,7 @@ static int e1000_tx_map(struct e1000_adapter *adapter, buffer_info->length = size; buffer_info->time_stamp = jiffies; buffer_info->next_to_watch = i; - buffer_info->dma = map[0] + offset; + buffer_info->dma = skb_shinfo(skb)->dma_head + offset; count++; len -= size; @@ -3947,7 +3947,7 @@ static int e1000_tx_map(struct e1000_adapter *adapter, buffer_info->length = size; buffer_info->time_stamp = jiffies; buffer_info->next_to_watch = i; - buffer_info->dma = map[f + 1] + offset; + buffer_info->dma = map[f] + offset; len -= size; offset += size; |