[ltp] Wifi slowdown

Paul Marwick linux-thinkpad@linux-thinkpad.org
Fri, 19 Apr 2013 16:14:35 +0100

I'm running Arch Linux on a T400. Its using this wireless interface:

03:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN 
[Shiloh] Network Connection

At home it connects to a Linksys WAG320N router. Until recently, I was 
getting a consistent 150 mbs connection to the router. I backup to an 
NFS share on a NAS (running OpenWRT). Recently, I found I was having 
some problems with rsync running to the NAS.

On checking, I've noticed that I no longer get a 150 mbs connect to the 
router - the highest connect speed I'm seeing now is 72 mbs. Not really 
a problem with internet use (my dsl connection is only running about 8 
mbs, but it certainly makes a difference when it comes to moving files 
around my local network.

The problem is confined to Arch - I've also got SalineOS and Salix on 
the T400, and both of them are still getting 150mbs connects to the router.

I suspect its got to be down to a change to the kernel. Arch is 
currently on 3.8.7, while SalineOS is 2.6.32 and Salix is on 3.2.29.

I've not been able to go back to a pre 3.8.x kernel, but I'm wondering 
if anyone else is seeing this sort of problem, or whether anyone can 
suggest other things I should be looking at to fix it?