Le mercredi 06 avril 2011 à 13:02 -0700, David Miller a écrit :
From: Arnaldo Carvalho de Melo acme@ghostprotocols.net Date: Wed, 6 Apr 2011 16:57:19 -0300
Something like ftrace code changing when the user inserts the first rule?
People wanting top performance disable it in the build, but thos wanting to stick to vendor provided kernels don't have that choice :)
Using ftrace-like stubs would be an interesting idea, and I highly encourage people to work on something like that.
However I want to reiterate that I think that real rules are installed in Jesse's case, and once he removes those the majority of the overhead will disappear. The FC14 workstation I'm using right now, on which I've made no modifications to the installer's netfilter settings, has the following rules:
[root@ilbolle davem]# iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT icmp -- anywhere anywhere ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh ACCEPT udp -- anywhere anywhere state NEW udp dpt:ipp ACCEPT udp -- anywhere 224.0.0.251 state NEW udp dpt:mdns ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ipp ACCEPT udp -- anywhere anywhere state NEW udp dpt:ipp REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT) target prot opt source destination REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT) target prot opt source destination [root@ilbolle davem]#
I suspect Jesse has something similar on his test box.
I suspect problem is worse than that.
I remember last time I work on a fedora kernel, it had conntrack enabled
And yes, conntrack can really slowdown a router, because of default parameters.
cat /proc/sys/net/nf_conntrack_max