netif_tx_queue_stopped(txq) is most of the time false.
Yet its cost is very expensive on SMP.
static inline int netif_tx_queue_stopped(const struct netdev_queue *dev_queue)
{
return test_bit(__QUEUE_STATE_XOFF, &dev_queue->state);
}
I saw this on oprofile hunting and bnx2 driver bnx2_tx_int().
We probably should split "struct netdev_queue" in two parts, one
being read mostly.
__netif_tx_lock() touches _xmit_lock & xmit_lock_owner, these
deserve a separate cache line.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
6a321cb370