Poor performance running Debian router

Hey guys. I've beaten my head against the wall for a few weeks on this and I
am about ready to give up.

I have a Debian box (clean install) with 2 nics.
First NIC is integrated into the mobo (nforce chipset) and uses the nvnet.o
module.
Second NIC is 3com 3C905 and uses the 3c59x module.

I have the 3Com as my external connection and the nforce as internal.
Everything is great until I install ipmasq. After that, my CPU system load
is constantly around 70% and when I ssh into the box it runs dog slow and
the SSH daemon starts sucking up like 10% CPU.

I cant figure out what process is taking up the 70% because top doesnt tell
me anything, but it doenst happen until I start routing.

I'd appreciate any help you guys can offer!

-Preston

"Preston Price" <(E-Mail Removed)> wrote
news:(E-Mail Removed):
> I have the 3Com as my external connection and the nforce as internal.
> Everything is great until I install ipmasq. After that, my CPU system
> load is constantly around 70% and when I ssh into the box it runs dog
> slow and the SSH daemon starts sucking up like 10% CPU.

More info please :

- ifconfig outpute
- netstat -rn output
- cpu freq, ram, ...
- network connexion : hub, switch, modem type, ...

Did you check the speed & duplex configuration of your nic ? (mii-tools
output), because you may have a system load du to resend ethernet packet
(caused by too much collision).



Regards

Okay here's what I've got:
AMD XP1600+
256M DDR RAM (Crucial)
3Com NIC (eth0)
NVIDIA integrated NIC (eth1)

ifconfig output:
eth0 Link encap:Ethernet HWaddr 00:60:97:B1:A5:E4
inet addr:24.119.2.xxx Bcast:255.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:13769 errors:0 dropped:0 overruns:0 frame:0
TX packets:2548 errors:0 dropped:0 overruns:0 carrier:9
collisions:0 txqueuelen:100
RX bytes:3228630 (3.0 MiB) TX bytes:397654 (388.3 KiB)
Interrupt:5 Base address:0xb800

eth1 Link encap:Ethernet HWaddr 00:E0:18:B05:99
inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2689 errors:0 dropped:0 overruns:0 frame:0
TX packets:2772 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:412601 (402.9 KiB) TX bytes:2566447 (2.4 MiB)
Interrupt:10

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:112 (112.0 b) TX bytes:112 (112.0 b)


netstat -rn output:
Destination Gateway Genmask Flags MSS Window irtt
Iface
24.119.2.0 0.0.0.0 255.255.255.0 U 40 0 0
eth0
192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0
eth1
0.0.0.0 24.119.2.1 0.0.0.0 UG 40 0 0
eth0

Network setup:
CableModem -> eth0 on router box.
Windows box -> eth1 on router box.

mii-tool output:
eth0: negotiated 100baseTx-FD, link ok
eth1: negotiated 100baseTx-FD, link ok

Also, here is the top few lines from 'top' (I just reconfigured it to do
routing again before sending this)
19:22:53 up 2 days, 24 min, 2 users, load average: 0.06, 0.01, 0.00
25 processes: 23 sleeping, 2 running, 0 zombie, 0 stopped
CPU states: 0.0% user, 22.4% system, 0.0% nice, 77.6% idle
Mem: 223656K total, 77620K used, 146036K free, 5004K buffers
Swap: 457844K total, 0K used, 457844K free, 43652K cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
2672 nacrotek 14 0 1768 1768 1596 R 3.8 0.7 0:38 sshd

The SSHD process is actually low on the CPU hit right now, it will go up to
10-20% depending on how quickly I type. That 3.8% is just from SSHing in and
running top.
The other ~20% is from loading up Google.

Thanks for the help!

-Preston



"Antoine EMERIT" <(E-Mail Removed)> wrote in message
news:<XnF94D6D91DD397Aantoineemerit@212.27.42.70>. ..
> "Preston Price" <(E-Mail Removed)> wrote
> news:(E-Mail Removed):
> > I have the 3Com as my external connection and the nforce as internal.
> > Everything is great until I install ipmasq. After that, my CPU system
> > load is constantly around 70% and when I ssh into the box it runs dog
> > slow and the SSH daemon starts sucking up like 10% CPU.
>
> More info please :
>
> - ifconfig outpute
> - netstat -rn output
> - cpu freq, ram, ...
> - network connexion : hub, switch, modem type, ...
>
> Did you check the speed & duplex configuration of your nic ? (mii-tools
> output), because you may have a system load du to resend ethernet packet
> (caused by too much collision).
>
>
>
> Regards

"Antoine EMERIT" <(E-Mail Removed)> wrote in message
news:XnF94D6D91DD397Aantoineemerit@212.27.42.70...
> "Preston Price" <(E-Mail Removed)> wrote
> news:(E-Mail Removed):
> > I have the 3Com as my external connection and the nforce as internal.
> > Everything is great until I install ipmasq. After that, my CPU system
> > load is constantly around 70% and when I ssh into the box it runs dog
> > slow and the SSH daemon starts sucking up like 10% CPU.
>
> More info please :
>
> - ifconfig outpute
> - netstat -rn output
> - cpu freq, ram, ...
> - network connexion : hub, switch, modem type, ...
>
> Did you check the speed & duplex configuration of your nic ? (mii-tools
> output), because you may have a system load du to resend ethernet packet
> (caused by too much collision).
>
>
>
> Regards

Hi Preston,

> ifconfig output:
> eth0 Link encap:Ethernet HWaddr 00:60:97:B1:A5:E4
> inet addr:24.119.2.xxx Bcast:255.255.255.255 Mask:255.255.255.0
^^^ ^^^^^^^^^^^^^^^

Looks kind of weird for me.
At least eth0 should have a valid IP and a reasonable broadcast address
like 24.119.2.255 (if BCast can be used in this interface anyway).

Is eth0 set up by dhcpd via your cable modem?
Or do you set the values locally?

Ciao

Ralf

Hmm, I didnt notice that.... The IP is obtained via DHCP from the Cable
Modem.
I didnt list my full IP here for security reasons.

I just looked at my redhat box (set up as a router until I get my debian box
figured out) and it has the same 255.255.255.255 Bcast but it doesnt suffer
from the same CPU sucking malady.

Thanks

-Preston

"Ralf Herrmann" <(E-Mail Removed)> wrote in message
news:c6ok8g$c9o$(E-Mail Removed)...
> Hi Preston,
>
> > ifconfig output:
> > eth0 Link encap:Ethernet HWaddr 00:60:97:B1:A5:E4
> > inet addr:24.119.2.xxx Bcast:255.255.255.255
Mask:255.255.255.0
> ^^^ ^^^^^^^^^^^^^^^
>
> Looks kind of weird for me.
> At least eth0 should have a valid IP and a reasonable broadcast address
> like 24.119.2.255 (if BCast can be used in this interface anyway).
>
> Is eth0 set up by dhcpd via your cable modem?
> Or do you set the values locally?
>
> Ciao
>
> Ralf

Hi Preston,

> I didnt list my full IP here for security reasons.

Ok, when i had sent the post, this reason also came into my mind;-)

> I just looked at my redhat box (set up as a router until I get my debian box
> figured out) and it has the same 255.255.255.255 Bcast but it doesnt suffer
> from the same CPU sucking malady.

Guess then there is no Broadcasting over your cable modem.
Should be ok, i just wondered.

Sorry it didn't help you.

Another thing i would point your attention to is your routing table.
I'm missing an entry for loop back routing, i.e.

127.0.0.1 0.0.0.0 255.0.0.0 [......] lo

or

127.0.0.1 127.0.0.1 255.0.0.0 [......] lo

...and i'm confused about those 0.0.0.0-entries in gateway fields for eth0/eth1.
ok, this may be a system dependend thing, but local interfaces usually show
127.0.0.1 as their gateway....but 0.0.0.0 might be ok for your distro.

CU

Ralf

Ralf Herrmann <(E-Mail Removed)> wrote
news:c6ok8g$c9o$(E-Mail Removed):
>> inet addr:24.119.2.xxx Bcast:255.255.255.255
>> Mask:255.255.255.0
> ^^^ ^^^^^^^^^^^^^^^
>
> Looks kind of weird for me.
> At least eth0 should have a valid IP and a reasonable broadcast
> address like 24.119.2.255 (if BCast can be used in this interface
> anyway).

255.255.255.255 is the "dhcp broadcast".

This is a local only broadcast address used to get an ip/netmask (and so
a broadcast) address, when the host has not get it's address yet from the
dhcp server.

This address is not supposed to be assigned to a specific client
interface. It's supposed to be aliased to the dhcp server interface
listening for client request.

But if you only have one host in front of the cable modem it shouldn't
hurt much. I supposed that this broadcast address is seted by the cable
modem to simplify reconnect.


> CPU states: 0.0% user, 22.4% system, 0.0% nice, 77.6% idle

More than 22% system cpu load on a AMD XP1600+, when you do nothing
important ! it's seems to be too much. Your kernel it doing somethink
that load it like retransmeeting network packet or waiting physical link.

> eth0 : carrier:9

How much carrier did you have each minute ?

It may load the system cpu (above comment) when you have a bad physical
link. And "carrier" means that you have an enthernet cable problem.

It you have a direct nic<->modem connection, try to insert a hub or a
switch.


Regards