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| 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/igb | |
| 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/igb')
| -rw-r--r-- | drivers/net/igb/igb_main.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c index 958b2879da48..ea17319624aa 100644 --- a/drivers/net/igb/igb_main.c +++ b/drivers/net/igb/igb_main.c @@ -3139,8 +3139,7 @@ static inline int igb_tx_map_adv(struct igb_adapter *adapter, /* set time_stamp *before* dma to help avoid a possible race */ buffer_info->time_stamp = jiffies; buffer_info->next_to_watch = i; - buffer_info->dma = map[count]; - count++; + buffer_info->dma = skb_shinfo(skb)->dma_head; for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) { struct skb_frag_struct *frag; @@ -3164,7 +3163,7 @@ static inline int igb_tx_map_adv(struct igb_adapter *adapter, tx_ring->buffer_info[i].skb = skb; tx_ring->buffer_info[first].next_to_watch = i; - return count; + return count + 1; } static inline void igb_tx_queue_adv(struct igb_adapter *adapter, |