[ardour-users] Jack uses 100% CPU and can't be killed

[Mark Knecht]

On Tue, 30 Nov 2004 12:40:34 -0500, ross at lug.udel.edu <ross at lug.udel.edu> wrote:
> On Tue, Nov 30, 2004 at 08:18:45AM -0800, Mark Knecht wrote:
> 
> 
> > On Tue, 30 Nov 2004 10:58:33 +0000, Ben Edwards <funkytwig at gmail.com> wrote:
> > > When I run jack with qjackctl it coplains about ALSA/midi/patchbay.  I
> > > went on IRC and as a result tried to start jack anyway.   It then
> > > consumed 100% cpu.  I couldent run top or ps!  In fact I couldent even
> > > shut down the PC properly - I had to hold my finger on the power
> > > button for 10 seconds to do a hard shutdown.
> > >
> > > BYW are the error messages loged to a file - I cant even copy/paste
> > > them from the message window.
> 
> I can pretty much guess what's going on.  You're running a 2.6 kernel
> right?  I had exactly the same symptoms and decided to stick with 2.4.
> 
> I'm not too sure of what's going wrong, but under recent 2.6 kernels,
> when a realtime application runs, it consumes tons of CPU and locks up
> a lot of system function.  The odd thing --- I could still use any
> browsers or shells I had already started.  Any file access would lock
> a process solid in an instant.
> 
> Like I said - I gave up, went back to 2.4.  The Jack FAQ has some
> notes on Jack maybe working with LD_ASSUME_KERNEL=2.4.19.  I don't
> remember if I had any luck with that.  I assume no, else I'd have
> stuck with 2.6.
> 
Possibly he's having this sort of problem. Good for him to post the
info like I asked. However, with help offline from Ingo, Lee Revell
and Fernando I've got none of these problems on any of my 2.6
machines.

2.6.9-rc2-mm4-VP-S7

Stable, low CPU usage and less than 1mS latency on my laptop.