From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>,
Tom Herbert <therbert@google.com>, jamal <hadi@cyberus.ca>
Subject: [PATCH net-next-2.6] net: eth_type_trans() should inline skb_pull()
Date: Sat, 01 May 2010 08:42:25 +0200 [thread overview]
Message-ID: <1272696145.2230.101.camel@edumazet-laptop> (raw)
840.000 pps instead of 800.000 pps on my 'old' machine, using RPS
Before patch, profile of CPU 0 (handling tg3 interrupts)
2167.00 13.9% __alloc_skb vmlinux
1908.00 12.3% eth_type_trans vmlinux
1125.00 7.2% __kmalloc_track_caller vmlinux
981.00 6.3% __netdev_alloc_skb vmlinux
925.00 5.9% _raw_spin_lock vmlinux
786.00 5.1% kmem_cache_alloc vmlinux
757.00 4.9% skb_pull vmlinux
698.00 4.5% tg3_read32 vmlinux
637.00 4.1% __slab_alloc vmlinux
620.00 4.0% tg3_poll_work vmlinux
576.00 3.7% get_rps_cpu vmlinux
448.00 2.9% bnx2_interrupt vmlinux
After (no more skb_pull, and eth_type_trans() not more expensive)
Predominant cost is memory allocator...
1625.00 12.4% eth_type_trans vmlinux
1468.00 11.2% __alloc_skb vmlinux
1004.00 7.6% __kmalloc_track_caller vmlinux
893.00 6.8% _raw_spin_lock vmlinux
738.00 5.6% __netdev_alloc_skb vmlinux
665.00 5.1% tg3_read32 vmlinux
656.00 5.0% kmem_cache_alloc vmlinux
655.00 5.0% __slab_alloc vmlinux
509.00 3.9% bnx2_interrupt vmlinux
483.00 3.7% tg3_poll_work vmlinux
455.00 3.5% _raw_spin_lock_irqsave vmlinux
330.00 2.5% get_rps_cpu vmlinux
286.00 2.2% nommu_map_page vmlinux
277.00 2.1% enqueue_to_backlog vmlinux
235.00 1.8% inet_gro_receive vmlinux
232.00 1.8% __copy_to_user_ll vmlinux
181.00 1.4% dev_gro_receive vmlinux
165.00 1.3% skb_gro_reset_offset vmlinux
(bnx2_interrupt is called, because irq 16 is shared on this machine on two nics...)
Thanks !
[PATCH net-next-2.6] net: eth_type_trans() should inline skb_pull()
With RPS, this patch can give a 5 % boost in performance.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 0c0d272..763524b 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -162,7 +162,8 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
skb->dev = dev;
skb_reset_mac_header(skb);
- skb_pull(skb, ETH_HLEN);
+ if (likely(skb->len >= ETH_HLEN))
+ __skb_pull(skb, ETH_HLEN);
eth = eth_hdr(skb);
if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
next reply other threads:[~2010-05-01 6:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-01 6:42 Eric Dumazet [this message]
2010-05-02 1:15 ` [PATCH net-next-2.6] net: eth_type_trans() should inline skb_pull() David Miller
2010-05-02 6:50 ` Eric Dumazet
2010-05-02 10:03 ` David Miller
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