[PKT_SCHED]: Reduce branch mispredictions in pfifo_fast_dequeue
authorThomas Graf <tgraf@suug.ch>
Mon, 18 Jul 2005 20:30:53 +0000 (13:30 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 18 Jul 2005 20:30:53 +0000 (13:30 -0700)
commit452f299da3253f65020143f743c2e207b752547b
tree56f02114d9e65d60c0f3a0658602e7e193f226bd
parentd7c7ed4dbc66c5f4dfa5615cdfc5009af3b3b137
[PKT_SCHED]: Reduce branch mispredictions in pfifo_fast_dequeue

The current call to __qdisc_dequeue_head leads to a branch
misprediction for every loop iteration, the fact that the
most common priority is 2 makes this even worse.  This issue
has been brought up by Eric Dumazet <dada1@cosmosbay.com>
but unlike his solution which was to manually unroll the loop,
this approach preserves the possibility to increase the number
of bands at compile time.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched/sch_generic.c