Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option

[Lee Revell]

On Wed, 2004-10-20 at 13:58, Timothy Miller wrote:
> Lee Revell wrote:
> > On Wed, 2004-10-20 at 11:35, Arjan van de Ven wrote:
> > 
> >>On Wed, Oct 20, 2004 at 11:46:32AM -0400, Timothy Miller wrote:
> >>
> >>>The rules about how long a hard irq would be allowed to run would have 
> >>>to be draconian.
> >>
> >>they already are.
> > 
> > 
> > The IDE I/O completion in hardirq context means that one can run for
> > almost 3ms.  Apparently at OLS it was decided that the target for
> > desktop responsiveness was 1ms.  So this is a real problem.
> 
> What is happening that takes 3ms, and why can't it be broken up?
> 

http://lkml.org/lkml/2004/7/24/26

> Are you talking here about PIO?  Is there a limited amount of time you 
> have to do the PIO before the data goes away?  It may be acceptable to 
> just live with PIO being slow, since high-performance systems will all 
> be using DMA anyhow.
> 

Nope, DMA.

> > 
> > What exactly do you mean by "draconian"?
> 
> In this case, I mean extremely harsh and restrictive.  Usually, it means 
> "excessively harsh", but in this case, I mean that in a good way.  :)
> 

Heh, I know what the word means, I was asking what the specific rules
are that could be considered as such.

Lee

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