Re: Interrupt starvation points

From: Daniel Walker
Date: Fri Feb 11 2005 - 16:57:11 EST


On Fri, 2005-02-11 at 12:04, Russell King wrote:
>
> Please substantiate your claim that up() is very expensive on ARM.
> I disagree:

I should have made it clear that I was talking about the RT version of
up() . The RT version doesn't have any assembly in it, and it is
expensive.

> Plus, after you've read the above code, wouldn't you think that adding
> the "enable interrupts + disable interrupts" around an up() operation
> (which itself immediately disables interrupts again) is just adding
> extra instructions to the kernel, which corresponds directly to lower
> performance?

Not in the RT case. However, I never said that was a proper fix, I was
just producing code that helped in my tests.

Daniel

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