[PATCH] Stackgap

[Julian Elischer]

Stack gap can actually improve performance in some cases..
the cache for the base of teh stack can become overly flushed by the 
fact that all stacks start with the same offset
from the page.  making this random can actually help this.


Robert Watson wrote:

>
> On Fri, 27 May 2005, Suleiman Souhlal wrote:
>
> In the past, substantial performance hits have been measured due to 
> poor stack alignment.  Specifically, in combination with less optimal 
> compiler behavior, the results have been pretty nasty.  Have you tried 
> micro-benchmarking a series of runs with this stack offset randomness 
> using floating point on stack arguments to see if there's a measurable 
> cost to moving the stack around?  Hopefull if all is well, there will 
> be little or no difference, but a small error here could result in a 
> substantial performance hit...

Stack gap can actually improve performance in some cases..

the cache for the base of teh stack can become overly flushed by the 
fact that all stacks
start with the same offset from the page.  making this random can 
actually help this.

>
>
> Robert N M Watson
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