Re: [PATCH 2/4] Core support for --combine -fwhole-program

[Adrian Bunk <bunk@stusta.de>]

On Fri, Aug 25, 2006 at 10:37:23AM +0100, David Woodhouse wrote:
> On Thu, 2006-08-24 at 23:33 +0200, Adrian Bunk wrote:
> > If a "build everything except for assembler files at once" approach is 
> > possible, it should be possible to revert this and get even further 
> > savings.
> 
> Only if we build _everything_ at once, which may take an insane amount
> of RAM. Doing it a directory at a time makes a certain amount of sense,
> and tends to combine the most incestuous code -- although maybe
> combinations like building arch/$ARCH/kernel/ with kernel/ (and likewise
> mm) could be an interesting experiment.

My hope is "insane" would be something like "1 GB of RAM" that is no 
longer insane on current computers. [1]

> I suspected that most of the 'further savings' to which you refer above
> could be achieved more easily with -ffunction-sections -fdata-sections
> --gc-sections

AFAIR -ffunction-sections/-fdata-sections cause some overhead in the 
resulting binary?

> dwmw2

cu
Adrian

[1] The interesting cases are embedded systems needing a small kernel
    that gets built on a much bigger system.
    Whether this should be the default compile mode for everyone is a
    different issue.

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed