Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

[Thomas Gleixner]

On Fri, 2004-10-29 at 15:33 -0400, Lee Revell wrote:
> On Fri, 2004-10-29 at 10:02 +0200, Ingo Molnar wrote:
> >    I know that Jackd does alot of precautions 
> >    to avoid unintentional scheduling (mlockall, the use of SCHED_FIFO), 
> >    but are you absolutely sure it doesnt happen? This scenario could be 
> >    excluded by measuring the time Jackd calls poll(), and comparing it
> >    to the expected value. [Or is this value already included in the 
> >    stats Rui collected? Maybe the "Maximum Process Cycle" value?]
> 
> Yes, this is already accounted for in the 'Maximum Process Cycle' value.
> This measures the time between returning from poll() and entering it
> again.  I will try to add some instrumentation to jackd and test this
> weekend.  I do agree that it could be a jackd bug; this would not be the
> first time the VP patches exposed bugs in other apps.
> 

Can you check out, whether the memory is getting low when you are doing
this tests ? The VM code has a serious problem, which might be related
to those latencies.

tglx


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