Hello.
I am working on what amounts to a Ethernet to Ultra-Wide Band (UWB)
converter box. Packets are simply routed from 1 interface to
another.
This box is based on an ARM7TDMI CPU, running Linux 2.4.26, and the
network throughput of the box is CPU-limited. How limited? The
100Mbps/FD Ethernet can do no better than 35Mbps.
I've discovered that I can improve Ethernet throughput by about %20 by
removing the the conntrack/masq support from the kernel. The removal
is good only as a test, though, since I need this functionality to
move the packets between interfaces.
This is the relevant config:
CONFIG_IP_NF_CONNTRACK=y
CONFIG_IP_NF_IPTABLES=y
CONFIG_IP_NF_NAT=y
CONFIG_IP_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=y
Enabled at boot time like this:
/sbin/iptables -t nat -A POSTROUTING -o uwb0 -j MASQUERADE
echo "1" > /proc/sys/net/ipv4/ip_forward
I wonder if I can improve conntrack/masq performance at the expense of
flexibility. This will be a closed system, with simple and static
routing. Are there any trade-offs I can make to sacrifice unneeded
flexibility in routing for reduced CPU utilization in conntrack/masq?
Thanks.
On 11/2/05, Steve Snyder <[email protected]> wrote:
> Hello.
>
> I am working on what amounts to a Ethernet to Ultra-Wide Band (UWB)
> converter box. Packets are simply routed from 1 interface to
> another.
>
> This box is based on an ARM7TDMI CPU, running Linux 2.4.26, and the
> network throughput of the box is CPU-limited. How limited? The
> 100Mbps/FD Ethernet can do no better than 35Mbps.
>
> I've discovered that I can improve Ethernet throughput by about %20 by
> removing the the conntrack/masq support from the kernel. The removal
> is good only as a test, though, since I need this functionality to
> move the packets between interfaces.
>
> This is the relevant config:
>
> CONFIG_IP_NF_CONNTRACK=y
> CONFIG_IP_NF_IPTABLES=y
> CONFIG_IP_NF_NAT=y
> CONFIG_IP_NF_NAT_NEEDED=y
> CONFIG_IP_NF_TARGET_MASQUERADE=y
>
> Enabled at boot time like this:
>
> /sbin/iptables -t nat -A POSTROUTING -o uwb0 -j MASQUERADE
> echo "1" > /proc/sys/net/ipv4/ip_forward
>
> I wonder if I can improve conntrack/masq performance at the expense of
> flexibility. This will be a closed system, with simple and static
> routing. Are there any trade-offs I can make to sacrifice unneeded
> flexibility in routing for reduced CPU utilization in conntrack/masq?
Hmmm... totally untested and don't know the details of UWB but...
can't you simply ether-bridge the interfaces instead of masquerading?
It should need less CPU
> Thanks.
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--
Greetz, Antonio Vargas aka winden of network
http://wind.codepixel.com/
[email protected]
[email protected]
Every day, every year
you have to work
you have to study
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On Wednesday 02 November 2005 15:23, Antonio Vargas wrote:
> On 11/2/05, Steve Snyder <[email protected]> wrote:
[snip]
> > I wonder if I can improve conntrack/masq performance at the expense of
> > flexibility. This will be a closed system, with simple and static
> > routing. Are there any trade-offs I can make to sacrifice unneeded
> > flexibility in routing for reduced CPU utilization in conntrack/masq?
>
> Hmmm... totally untested and don't know the details of UWB but...
> can't you simply ether-bridge the interfaces instead of masquerading?
> It should need less CPU
Hmm... I'm not familiar with ether-bridge, and Google turns up only
commercial products and BSD references.
Pointer to info, please?
Thanks.
On Wed, 2 Nov 2005 15:51:52 -0500
Steve Snyder <[email protected]> wrote:
> On Wednesday 02 November 2005 15:23, Antonio Vargas wrote:
> > On 11/2/05, Steve Snyder <[email protected]> wrote:
> [snip]
> > > I wonder if I can improve conntrack/masq performance at the expense of
> > > flexibility. This will be a closed system, with simple and static
> > > routing. Are there any trade-offs I can make to sacrifice unneeded
> > > flexibility in routing for reduced CPU utilization in conntrack/masq?
> >
> > Hmmm... totally untested and don't know the details of UWB but...
> > can't you simply ether-bridge the interfaces instead of masquerading?
> > It should need less CPU
>
> Hmm... I'm not familiar with ether-bridge, and Google turns up only
> commercial products and BSD references.
It in the kernel already! Look at
http://linux-net.osdl.org/index.php/Bridge
For more info
--
Stephen Hemminger <[email protected]>
OSDL http://developer.osdl.org/~shemminger