RFC: Primary architecture promotion requirements

Brendan Conoboy blc at redhat.com
Tue Mar 20 16:50:02 UTC 2012

On 03/20/2012 09:37 AM, drago01 wrote:
>> I'm a big fan of cross compilation, but introducing it into Fedora in order
>> to support ARM seems unlikely to succeed for too many reasons to go into.
> The reasons are? ....

Okay, why not?

The ones off the top of my head, and this is by no means exhaustive:

1. Fedora Policy (Which I imagine is based on the technical foundation 
of the following 5+ points and others I'm unaware of).

2. Many packages assume a native execution environment which will not 
exist.  Incredible undertaking to move 11000 packages to cross 
compilation framework.

3. Absence of arm-linux cross compilers in the distribution.

4. If there were arm-linux cross compilers, how do you keep them in sync 
with native gcc?

5. Where does the sys-root for an arm-linux cross compiler come from?

6. Would koji then be native/cross ambidextrous?  Who is going to do that?

For all these reasons and more we're not proposing cross compilation for 
ARM.  Just doing so defies what it means to be PA.

> The hardware is way slower ... so we can just build on faster hardware
> (x86_64). Which is the only sane way to do it.
> Trying to build on ARM directly is kind of a gimmick but nothing one
> can seriously use to build a whole operating system. (Yes it works but
> it is way to slow).

In couple years the hardware is going to be surprisingly comparable or 
exceed to what you're see on x86, especially as the number of cores 
skyrockets while the GHz continue to climb.  It's not a gimmick, we're 
just preparing for the future before it gets here.  The only problem we 
face is that those cores are in multiple CPUs so we can't 'make -j' our 
way out of the build system problem.

Brendan Conoboy / Red Hat, Inc. / blc at redhat.com

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