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Message-ID: <5bdc1c8b0510121211g5a46282fm2e34188875261bb7@mail.gmail.com>
Date: Wed, 12 Oct 2005 12:11:30 -0700
From: Mark Knecht <markknecht@gmail.com>
To: Lee Revell <rlrevell@joe-job.com>
Subject: Re: 2.6.14-rc4-rt1
Cc: Fernando Lopez-Lezcano <nando@ccrma.stanford.edu>,
       Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
       Thomas Gleixner <tglx@linutronix.de>,
       Steven Rostedt <rostedt@goodmis.org>, dwalker@mvista.com,
       david singleton <dsingleton@mvista.com>
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On 10/12/05, Lee Revell <rlrevell@joe-job.com> wrote:
> On Wed, 2005-10-12 at 14:25 -0400, Lee Revell wrote:
> > On Wed, 2005-10-12 at 11:00 -0700, Mark Knecht wrote:
> > > On 10/12/05, Lee Revell <rlrevell@joe-job.com> wrote:
> > > > Sounds like an application bug (some JACK client doing something not RT
> > > > safe).  Can you reproduce the xruns if you just run jackd with no
> > > > clients?
> > >
> > > I don't know. These xruns take hours to generate. I'd probably have to
> > > dedicate a whole day of doing nothing on the machine to try, and then
> > > if I didn't produce anything I'm not sure what it proves. If I do get
> > > one then we get to see if there's data.
> >
> > A much easier solution is to recompile JACK with the
> > --enable-preemption-check option.  This activates the in-kernel
> > debugging mechanism that causes a stack dump when an RT task schedules.
> > It has been used to find tricky bugs in Hydrogen and Freqtweak already.
>
> I should also remind you that if you pursue the
> --enable-preemption-check option, then we'll be well outside of kernel
> land so you might want to take it up on the JACK list.
>
Good point.

I've just built with this feature. I'll try it out for a while and ask
questions on that list while I'm configured this way.

Thanks for the idea.

Cheers,
Mark
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