[TAG] using smp kernel, get 100% cpu usage one one cpu without any real load on the system

[jim ruxton]

Thanks Ben,
> > Hi I'm on a P4 running an smp kernel ie.
> > 
> > uname -a :
> >  
> > Linux jims-laptop 2.6.20-16-386 #2 Sun Sep 23 19:47:10 UTC 2007 i686
> > GNU/Linux
> > 
> > For some reason occasionaly one of my cpu's runs away and starts showing
> > 100% cpu usage, however top only shows the program using the most cpu at
> > 7% or less. Where is that 93% going? This is driving me crazy. I have to
> > reboot the machine to get it back to normal. I've tried Fedora and
> > Kubuntu. Though Kubuntu appeared more stable it still happened. Played
> > around with changing max_cstate without success.I've just downgraded to
> > a 386 kernel to see if that helps. This isn't a real solution however.
> > Do you have any suggestions? I've asked around on forums and irc
> > channels without luck. Thanks.
> 
> One of the things that might be worth trying is reducing everything to a
> minimum and seeing if it still happens. That is, try booting into single
> mode and shutting down any non-critical processes, then just letting the
> system "cook" for a little while. If it happens again, you've most
> likely narrowed it down to either a) the kernel or b) the hardware. For
> troubleshooting the former, check out the kernel compilation options (I
> seem to recall a developer/debugging option accessible via 'make
> config'.) For the latter, try a hairdryer aimed at the offending CPU. :)
I tried switching into Single User Mode once the 1 processor jumped to
100% but it didn't seem to change anything. I've tried unloading some
modules but I keep getting Resource currently unavailable after running
rmmod. Do you know what this would mean in this context? This glitch is
hard to track down because sometimes it doesn't happen for a day or so
after I've rebooted.
jim

> 
>