Re: New (now current development process)

Adrian Bunk
2005-11-01T14:08:18Z

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