small kernel kernel option...

Julian Elischer julian at freebsd.org
Fri Feb 28 05:15:06 UTC 2014


On 2/27/14, 5:48 AM, John-Mark Gurney wrote:
> I'm about to commit a change to sha256 to speed it up, but the cost
> of that speed up is an increase in code/data size from just under 1k
> to almost 9k (as measured on amd64)...  this increase is from unrolling
> a loop..
>
> Maybe we should have a global kernel option, SMALL_KERNEL, or something
> similar that can be used to shrink code size for those that are trying
> to build small embedded devices...
>
> Or do we already have this option, but I just don't know about it?
>
> I know 8k isn't much, but, a billion here and a billion there and pretty
> soon you're talking about real money.. :)
>
> Comments?
>
it's the same as the old "space vs time" optimisations in UFS.

maybe "OPTIMIZE_FOR_SPACE" vs "OPTIMIZE_FOR_SPEED"



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