From adc9300e78e6091a7eaa1821213836379d4dbaa8 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 17 Nov 2011 03:13:26 +0000 Subject: net: use jump_label to shortcut RPS if not setup Most machines dont use RPS/RFS, and pay a fair amount of instructions in netif_receive_skb() / netif_rx() / get_rps_cpu() just to discover RPS/RFS is not setup. Add a jump_label named rps_needed. If no device rps_map or global rps_sock_flow_table is setup, netif_receive_skb() / netif_rx() do a single instruction instead of many ones, including conditional jumps. jmp +0 (if CONFIG_JUMP_LABEL=y) Signed-off-by: Eric Dumazet CC: Tom Herbert Signed-off-by: David S. Miller --- net/core/net-sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/core/net-sysfs.c') diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 602b1419998c..db6c2f83633f 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -606,9 +606,12 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue, rcu_assign_pointer(queue->rps_map, map); spin_unlock(&rps_map_lock); - if (old_map) + if (map) + jump_label_inc(&rps_needed); + if (old_map) { kfree_rcu(old_map, rcu); - + jump_label_dec(&rps_needed); + } free_cpumask_var(mask); return len; } -- cgit v1.2.3