fedora 14 kernel performance with ip forwarding workload
Eric Dumazet
eric.dumazet at gmail.com
Wed Apr 6 20:18:56 UTC 2011
Le mercredi 06 avril 2011 à 13:02 -0700, David Miller a écrit :
> From: Arnaldo Carvalho de Melo <acme at 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 at 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 at 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
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