Re: [PATCH] local_irq_disable removal

Esben Nielsen
2005-06-11T19:35:46Z

On Sat, 11 Jun 2005, Ingo Molnar wrote:

>
> * Daniel Walker <dwalker@mvista.com> wrote:
>
> > > The current soft-irq states only gives us better hard-irq latency but
> > > nothing else. I think the overhead runtime and the complication of the
> > > code is way too big for gaining only that.
> >
> > Interrupt response is massive, check the adeos vs. RT numbers . They
> > did one test which was just interrupt latency.
>
> 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 have another problem:
I can't hide that my aim is to make task-latencies deterministic.
The worry is local_irq_disable() (and preempt_disable()). I can undefine
it and therefore find where it is used. I can then look at the code, make
it into raw_local_irq_disable() or try to make a lock.
In many cases the raw-irq disable is the best and simplest when I am only
worried about task-latencies. But now Daniel and Sven wants to use the
distingtion between raw_local_irq_disable() and local_irq_disable() to
make irqs fast.
We do have a clash of notations. Any idea what to do? I mentioned
local_
raw_local_
hard_local_

Would that work?

> Ingo

Esben