RFC: Primary architecture promotion requirements

[drago01]

On Tue, Mar 20, 2012 at 5:50 PM, Brendan Conoboy <blc at redhat.com> wrote:
> 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).

I said "technical" so lets take policy aside ...

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

qemu? Should be still faster then doing the whole build on arm.

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

Err yeah but nothing that can't be fixed.

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

Build from the same srpm.

> 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?

No real answers to them yet but fixing them seems to be easier then
"make arm as fast as x86_64".

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

We should somehow define what a PA is then. I wouldn't have added
"built on native hardware" because that does not really seem to
matter.

>
>> 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.

Might be true might be not ... we are talking about the next couple of
months not years.

>  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.

Huh? Not sure I follow here.

Also I am not opposed to having ARM as PA, I just don't really think
we should do it the way it is proposed here (build on hardware that is
way slower then the rest of the builders).