Re: [patch 00/2] improve .text size on gcc 4.0 and newer compilers

Willy Tarreau
2005-12-30T09:30:28Z

On Fri, Dec 30, 2005 at 09:33:14AM +0100, Jesper Juhl wrote:
> On 12/30/05, Willy Tarreau <willy@w.ods.org> wrote:
>
> >
> > Can't we elect a recommended gcc version that distro makers could
> > ship under the name kgcc as it has been the case for some time,
> > and try to stick to that version for as long as possible ? The only
> > real reason to upgrade it would be to support newer archs, while at
> > the moment, we try to support compilers which are shipped as default
> > *user-space* compilers.
> >
> As I see it, doing that would
> - put extra work on distributors.

In the short term, yes. In the mid-term, I don't think so. Having one package
which does not need to change and another one which evolves regardless of
kernel needs is less work than ensuring that a single package is still
compatible with everyone's needs. Think about support too : "what gcc version
did you use ?" would simply become "did you build with kgcc ?"

> - bloat users systems with the need to have two gcc versions installed.

$ size /usr/lib/gcc-lib/i586-pc-linux-gnu/3.3.6/cc1
text data bss dec hex filename
3430228 2680 746688 4179596 3fc68c /usr/lib/gcc-lib/i586-pc-linux-gnu/3.3.6/cc1

You don't even need libgcc nor c++ to build the kernel. Anyway, it should
not be an absolute requirement, but the *recommended* and *supported* version.

> - decrease testing with different gcc versions, which sometimes uncover bugs.

gcc testing should not consume kernel developpers' time, but gcc's users.
How many kernel bugs have finally been attributed to a recent change in gcc ?
A lot I think. Uncovering bugs in gcc is useful but not the primary goal of
kernel developpers.

> Jesper Juhl <jesper.juhl@gmail.com>

Willy