small kernel kernel option...

[Warner Losh]

On Feb 26, 2014, at 2:24 PM, John-Mark Gurney <jmg at funkthat.com> wrote:

> Warner Losh wrote this message on Wed, Feb 26, 2014 at 14:02 -0800:
>> 
>> On Feb 26, 2014, at 1:48 PM, John-Mark Gurney <jmg at funkthat.com> 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?
>> 
>> I?d prefer something that?s more like OPTIMIZE_SIZE or OPTIMIZE_SPEED.
> 
> Shall I add OPTIMIZE_SIZE and make OPTIMIZE_SPEED the default (by being
> unspecified)?  I don't know of a good way w/ config to make sure only
> one or the other is specified (besides having some shared header #error
> if they are.. and though you could say if neither is specified, balance
> that optimization, but I don't see a use for it…

I’d toss it into a header. No reason that config needs to error out…

Warner