Subject: Re: jerky interactive behavior
To: None <>
From: Steven M. Bellovin <>
List: current-users
Date: 01/22/2007 09:56:46
On Sat, 20 Jan 2007 21:23:22 -0500
"Steven M. Bellovin" <> wrote:

> I recently upgraded my kernel to one from January 8 (and then to one
> from today).  Before that, I'd been running a mid-December -current.
> Interactive performance on my Thinkpad T42 has become completely
> unacceptable.  Something else -- I have no idea what -- occasionally
> grabs the CPU.  Moving the mouse shows jerky cursor motion, I get
> doubled input characters, etc.  ps and top show that the machine is
> mostly idle, though xosview sometimes shows brief spurts of 100% busy.
> It isn't swapping (it's got 2G of RAM), the interrupt load doesn't
> seem high (about 1.4-1.6K/sec, with HZ set to 1000), etc.  
> Is anyone else seeing this?  Anything I should do to tune it?  Might
> the new scheduler code be part of it?
Here's a possibly-interesting data point.  I was using my laptop on
the train this morning, without trouble.  As soon as I plugged in my
EVDO Cardbus card, I started seeing the hesitations and jerkiness in
mouse movements.  When I was having trouble over the weekend, it was
while using a mini-PCI ath0.  Might those be linked?  (It's a bit odd to
think that I'd have trouble with those and not my GigE wm0...)

		--Steve Bellovin,