Re: [PATCH v7 07/11] arch/x86: enable task isolation functionality

Thomas Gleixner
2015-10-01T10:11:25Z

On Thu, 1 Oct 2015, Christoph Lameter wrote:
> On Thu, 1 Oct 2015, Thomas Gleixner wrote:
>
> > And I really want to see a proper engineering for that isolation
> > stuff, which can be done with an out of tree patch set in the first
> > place. But sure, it's more convenient to push crap into mainline and
> > let everyone else deal with the fallouts.
>
> Yes lets keep the half baked stuff out please. Firing a timer that signals
> the app via a signal causes an event that is not unlike the OS noise that
> we are trying to avoid. Its an asynchrononous event that may interrupt at
> random locations in the code. In that case I would say its perfectly fine
> to use the tick and other timer processing on the processor that requested
> it. If you really want low latency and be OS intervention free then please
> do not set up timers. In fact any signal should bring on full OS services
> on a processor.

Right. That's a recommendation to the application developer, which he
can follow or not. And he has to deal with the consequences if not.

Thanks,

tglx