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

[K.R. Foley]

Ingo Molnar wrote:
> * Ingo Molnar <mingo@xxxxxxx> wrote:
>
>
> > > removing the poll() lines doesnt seem to impact the quality of the
> > > data, but i still see roughly 50 usecs added to the 'real' latency
> > > that i see in traces.
> >
> > this i think is related to what Thomas observed, that there's a new
> > irqs-off critical section somewhere. (it's in the new priority
> > handling code i think.)
>
>
> ah, found it. Only RT tasks were supposed to get special priority
> handling, while in fact all tasks got it - so when Thomas ran hackbench
> (Thomas, you did, right?) it created an O(nr_hackbench) overhead within
> the mutex code ... I've uploaded -V0.6.5 to the usual place:
>
>   http://redhat.com/~mingo/realtime-preempt/

V0.6.5 built and booted fine on my SMP workstation. However, just a few 
minutes after booting it exhibited behavior like a system does when you 
can't fork any new processses.
The system was responsive.
I could switch between windows.
I could switch from X to a virtual terminal.
I could type in commands but they never return.
At the virtual terminal login I could type the login but never get a 
passwd prompt.
Nothing in the logs during this timeframe.
Reset button was the only way to recover.

kr

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