From fbf8866d65d5de84f75563eb0edd7fc27dbe9a90 Mon Sep 17 00:00:00 2001
From: Shawn Bohrer <sbohrer@rgmadvisors.com>
Date: Mon, 7 Oct 2013 11:01:40 -0500
Subject: [PATCH] net: ipv4 only populate IP_PKTINFO when needed
The since the removal of the routing cache computing
fib_compute_spec_dst() does a fib_table lookup for each UDP multicast
packet received. This has introduced a performance regression for some
UDP workloads.
This change skips populating the packet info for sockets that do not have
IP_PKTINFO set.
Benchmark results from a netperf UDP_RR test:
Before 89789.68 transactions/s
After 90587.62 transactions/s
Benchmark results from a fio 1 byte UDP multicast pingpong test
(Multicast one way unicast response):
Before 12.63us RTT
After 12.48us RTT
Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/ip.h | 2 +-
net/ipv4/ip_sockglue.c | 5 +++--
net/ipv4/raw.c | 2 +-
net/ipv4/udp.c | 2 +-
4 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h
index 16078f422397..b39ebe5339ac 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -459,7 +459,7 @@ int ip_options_rcv_srr(struct sk_buff *skb);
* Functions provided by ip_sockglue.c
*/
-void ipv4_pktinfo_prepare(struct sk_buff *skb);
+void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc);
int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 56e34457ac07..0626f2cb192e 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1052,11 +1052,12 @@ static int do_ip_setsockopt(struct sock *sk, int level,
* destination in skb->cb[] before dst drop.
* This way, receiver doesnt make cache line misses to read rtable.
*/
-void ipv4_pktinfo_prepare(struct sk_buff *skb)
+void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb)
{
struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb);
- if (skb_rtable(skb)) {
+ if ((inet_sk(sk)->cmsg_flags & IP_CMSG_PKTINFO) &&
+ skb_rtable(skb)) {
pktinfo->ipi_ifindex = inet_iif(skb);
pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
} else {
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index b2fa14c1a6f1..41e1d2845c8f 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -299,7 +299,7 @@ static int raw_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
/* Charge it to the socket. */
- ipv4_pktinfo_prepare(skb);
+ ipv4_pktinfo_prepare(sk, skb);
if (sock_queue_rcv_skb(sk, skb) < 0) {
kfree_skb(skb);
return NET_RX_DROP;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 262ea3929da6..4226c53daaed 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1544,7 +1544,7 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
rc = 0;
- ipv4_pktinfo_prepare(skb);
+ ipv4_pktinfo_prepare(sk, skb);
bh_lock_sock(sk);
if (!sock_owned_by_user(sk))
rc = __udp_queue_rcv_skb(sk, skb);
--
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