Re: [PATCH] local_irq_disable removal

[Esben Nielsen]

On Mon, 13 Jun 2005, Sven-Thorsten Dietrich wrote:

> On Sat, 2005-06-11 at 22:03 +0200, Ingo Molnar wrote:
> > * Esben Nielsen <simlo@xxxxxxxxxx> wrote:
> > 
> > > > the jury is still out on the accuracy of those numbers. The test had 
> > > > RT_DEADLOCK_DETECT (and other -RT debugging features) turned on, which 
> > > > mostly work with interrupts disabled. The other question is how were 
> > > > interrupt response times measured.
> > > > 
> > > You would accept a patch where I made this stuff optional?
> > 
> > I'm not sure why. The soft-flag based local_irq_disable() should in fact 
> > be a tiny bit faster than the cli based approach, on a fair number of 
> > CPUs. But it should definitely not be slower in any measurable way.
> > 
> 
> Is there any such SMP concept as a local_preempt_disable()  ?
> 
You must think of preempt_disable() ? Except for the interface is a little
bit different using flags in local_irq_save(), preempt_disable() works
exactly the same way, blocking for everything but interrupts - on the
_local_ CPU. (Under PREEMPT_RT it ofcourse also blocks for threaded IRQ
handlers.)


Esben

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