linux/net/netfilter/xt_cpu.c, branch v3.7.3Linux kernel source treehttps://git.amat.us/linux/atom/net/netfilter/xt_cpu.c?h=v3.7.32011-01-18T05:33:54Znetfilter: xtables: add missing aliases for autoloading via iptables2011-01-18T05:33:54ZJan Engelhardtjengelh@medozas.de2011-01-18T05:30:13Zurn:sha1:f1e231a356f90a67f8547c2881a62c92084683c6
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
netfilter: add xt_cpu match2010-07-23T10:59:36ZEric Dumazeteric.dumazet@gmail.com2010-07-23T10:59:36Zurn:sha1:e8648a1fdb54da1f683784b36a17aa65ea56e931
In some situations a CPU match permits a better spreading of
connections, or select targets only for a given cpu.
With Remote Packet Steering or multiqueue NIC and appropriate IRQ
affinities, we can distribute trafic on available cpus, per session.
(all RX packets for a given flow is handled by a given cpu)
Some legacy applications being not SMP friendly, one way to scale a
server is to run multiple copies of them.
Instead of randomly choosing an instance, we can use the cpu number as a
key so that softirq handler for a whole instance is running on a single
cpu, maximizing cache effects in TCP/UDP stacks.
Using NAT for example, a four ways machine might run four copies of
server application, using a separate listening port for each instance,
but still presenting an unique external port :
iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 0 \
-j REDIRECT --to-port 8080
iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 1 \
-j REDIRECT --to-port 8081
iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 2 \
-j REDIRECT --to-port 8082
iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 3 \
-j REDIRECT --to-port 8083
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>