From e88721f87d8caa679e62d6004a9a5661f1ac7b0e Mon Sep 17 00:00:00 2001 From: Krishna Kumar Date: Wed, 18 Feb 2009 17:55:02 -0800 Subject: [PATCH] net: Optimize skb_tx_hash() by eliminating a comparison Optimize skb_tx_hash() by eliminating a comparison that executes for every packet. skb_tx_hashrnd initialization is moved to a later part of the startup sequence, namely after the "random" driver is initialized. Rebooted the system three times and verified that the code generates different random numbers each time. Signed-off-by: Krishna Kumar Signed-off-by: David S. Miller --- net/core/dev.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index d393fc997cd9..5493394118fb 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1745,17 +1745,11 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev, } static u32 skb_tx_hashrnd; -static int skb_tx_hashrnd_initialized = 0; static u16 skb_tx_hash(struct net_device *dev, struct sk_buff *skb) { u32 hash; - if (unlikely(!skb_tx_hashrnd_initialized)) { - get_random_bytes(&skb_tx_hashrnd, 4); - skb_tx_hashrnd_initialized = 1; - } - if (skb_rx_queue_recorded(skb)) { hash = skb_get_rx_queue(skb); } else if (skb->sk && skb->sk->sk_hash) { @@ -5291,6 +5285,14 @@ static int __init net_dev_init(void) subsys_initcall(net_dev_init); +static int __init initialize_hashrnd(void) +{ + get_random_bytes(&skb_tx_hashrnd, sizeof(skb_tx_hashrnd)); + return 0; +} + +late_initcall_sync(initialize_hashrnd); + EXPORT_SYMBOL(__dev_get_by_index); EXPORT_SYMBOL(__dev_get_by_name); EXPORT_SYMBOL(__dev_remove_pack); -- GitLab