Re: New (now current development process)

[Adrian Bunk <bunk@stusta.de>]

On Mon, Oct 31, 2005 at 04:34:08PM -0800, Andrew Morton wrote:
> Linus Torvalds <torvalds@osdl.org> wrote:
> >
> > 
> > 
> > On Mon, 31 Oct 2005, Andrew Morton wrote:
> > > 
> > > Are you sure these kernels are feature-equivalent?
> > 
> > They may not be feature-equivalent in reality, but it's hard to generate 
> > something that has the features (or lack there-of) of old kernels these 
> > days. Which is problematic.
> 
> Probably.
> 
> > But some of it is likely also compilers. gcc does insane padding in many 
> > cases these days. 
> 
> 2.6.14 `make allnoconfig':
> 
> gcc-2.95.4:
> 
> 	bix:/usr/src/25> size vmlinux 
> 	   text    data     bss     dec     hex filename
> 	 665502  152379   55120  873001   d5229 vmlinux
> 
> gcc version 4.1.0 20050513 (experimental):
> 
> 	bix:/usr/src/25> size vmlinux
> 	   text    data     bss     dec     hex filename
> 	 761415  151851   55280  968546   ec762 vmlinux

That's not a fair comparison.

If you do not tell gcc to optimize for size you can't expect it to 
produce small code.

The following is with allnoconfig + CONFIG_EMBEDDED=y + intelligent 
setting of the options shown by "make oldconfig" after setting 
CONFIG_EMBEDDED=y (the third kernel is built without 
-fno-unit-at-a-time):

   text    data     bss     dec     hex filename
 522545   77694   31256  631495   9a2c7 vmlinux-2.95
 436878   76594   32248  545720   853b8 vmlinux-4.0
 429420   76370   32184  537974   83576 vmlinux-4.0-unit-at-a-time


> (There's a new reason for retaining gcc-2.95.x support)
>...

There's a new reason for removing gcc-2.95.x support.  ;-)

cu
Adrian

-- 

       "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