Network is slowing down my system

I have a problem that just started recently. When my network is running, my cpu load is very high. I am running 11.3 on a Thinkpad T61. When the my network is up, either with Networkmanager or ifup/ifdown, one of the processor gets loaded down. It is so bad that my keystrokes are not captured properly. When I shut down the network using “service network stop”, everything works properly and the cpu load drops.
Any ideas?

Try looking at the ‘top’ command which proccess is eating your cpu. I have similar problem with LotusNotes - when it’s connected to the server one core of the processor is still busy…

I checked top and it is “events/0” or “events/1”. It is only one or the other, and I think it depends on which processor is being loaded up. This doesn’t really tell me anything. If I watch the graphical monitor, the processor is cycling between almost no activity to 100% every few seconds. I have tried shutting down all of my network daemons, and it is not any of them. It is only when I shut down the network that the loading comes down. I have had 11.3 running on the laptop for months now, and I can’t remember changing anything to do with networking, so I think it might have been an automatic update that started this.

Take a look at similiar problem:

events/0 process usage

Maybe you should also check if your NIC is using proper module. Or maybe your nic is broken?

I had already looked at that thread. I don’t think the nic is broken, because when I have the network running, I have full connectivity. The loaded modules seem to be what I remember having in the past.
There is one other thing that has shown up lately, but I don’t really think it is related. That is, when I click on my home directory for the first time after logging in, Dolphin takes a long time before displaying the contents. It also did this when I opened a terminal window and typed “ls” to get a directory listing. This was accompanied by a lot of disk activity, so I think it has to do with how the system keeps track of files.

Look at the output of ‘cat /proc/interrupts’. Do any of the devices show an
unusually high count?

I’m not sure what unusually high is, but iwlagn is sending about 50-100 interrupts a second to processor #0. The system monitor shows processor #2 with the heavy loading. I’m not sure what the number conventions are though, because the output from /proc/interrupts is processors #0 and #1, and the system monitor shows processors #1 and #2. I would assume #0 corresponds to #1 and #1 to #2.

On 11/23/2010 11:06 AM, timmytonawanda wrote:
>
> I’m not sure what unusually high is, but iwlagn is sending about 50-100
> interrupts a second to processor #0. The system monitor shows processor
> #2 with the heavy loading. I’m not sure what the number conventions are
> though, because the output from /proc/interrupts is processors #0 and
> #1, and the system monitor shows processors #1 and #2. I would assume
> #0 corresponds to #1 and #1 to #2.

That number seems pretty high. On my box, I’m getting 17/sec on the interrupt
that controls a USB hub, the graphics adapter, and b43.

What is your wifi card? Post the output of ‘/sbin/lspci -nmn’. Are you actually
using the wireless?

Ok, so I started up the network and the loading skyrocketed. I then started removing modules related first to wireless. When I removed e1000e, the system returned to normal. I then restarted the network and reloaded iwlagn. Wireless now works with no excessive system load, but wired connnection is disabled.

On 11/23/2010 12:36 PM, timmytonawanda wrote:
>
> Ok, so I started up the network and the loading skyrocketed. I then
> started removing modules related first to wireless. When I removed
> e1000e, the system returned to normal. I then restarted the network and
> reloaded iwlagn. Wireless now works with no excessive system load, but
> wired connnection is disabled.

As e1000e is a driver for an Ethernet interface, I would expect that. You can
throttle the interrupt rate for that device by using


sudo /sbin/modprobe e1000e InterruptThrottleRate=YYYY

where YYYY is 0 (off), 1 (dynamic), 3 (dynamic-conservative - default), 4
(simplified balancing), or 100-100000 (the maximum rate allowed). I would try
various values starting with 100 to see if these help. If this helps, then (as
root) create a file /etc/modprobe.d/50-e1000e.conf containing the line “options
e1000e InterruptThrottleRate=XXX”.