[fedora-arm] ARMv7 rootfs/repository?

Gordan Bobic gordan at bobich.net
Thu Dec 23 14:50:22 UTC 2010


Peter Robinson wrote:

>>>> are you sure the fp arg style is a kernel issue?
>>>> are there system calls that take floats (not in structs or arrays
>>>> but as a single argument)?
>>> >From all the documentation about it seems so. You need to remember
>>> there's a lot of mainline distros (and I'm not talking about small
>>> embedded ones) looking to move to arm7 + hardfp but none that have yet
>>> done so. There's lots of notes and people that have done customer
>>> recompiles etc for testing and eval purposes but none that have
>>> actually done it yet across the entire mainline distro to run
>>> everything from apache to gnome.
>>>
>>>> i could be totally wrong. it just seems almost there...
>>> Its is but that doesn't mean there's still not a lot of work to do.
>>> The Fedora ARM team has had issues with gcc / glibc etc just trying to
>>> get Fedora 13 compiled on on arm5tel. I've seen mention in the thread
>>> "but it works great with ICC" but you have to remember Fedora is an
>>> open distro so we're not going to be using a closed compiler to fix
>>> the problem.
>> ICC is x86 only. I mentioned it to illustrate that there is so much GCC
>> specific stuff in important core libraries like glibc that it is
>> unlikely we will get it working with any other compiler any time soon.
>> There are actually two problems regarding this:
> 
> I thought you were referring to ImageCraft C Compiler which arm and others
> http://www.imagecraft.com/

No, I was refering to Intel C Compiler:
http://software.intel.com/en-us/articles/intel-compilers/

>> 1) People shouldn't be writing code that isn't portable across compilers.
> 
> I don't disagree.
> 
>> 2) GCC isn't a very good compiler performance-wise - not by a long way.
> 
> It doesn't matter, its currently the core compiler that Fedora uses
> and hence it what we need to get to work. When upstream Fedora changes
> to something else so can we but I don't see that happening in the
> short to medium term. In fact I suspect that its more likely to get
> upstream gcc integrate some LLVM perf improvements before that
> happens.

Maybe, maybe not. I'm planning to put up a yum repository of ICC-built 
RHEL6 RPMs.

Not everything will build.

Not everything that builds will work.

Not everything that works will necessarily bring performance advantages 
  - for example, on RHEL5, after extensive testing and a lot of attempts 
at tweaks, perl's performance just wouldn't budge - it's as slow when 
built using ICC as with GCC, and it took a lot of trial and error to 
just get it to build at all, let alone pass the test suite.

But of the things that do, build and work, the improvement is definitely 
worth having.

Of course I don't expect Fedora to switch to a commercial, non-GPL 
compiler. But considering that GCCs performance has degraded as often as 
it has improved between releases, I'm not too hopeful about the gap 
closing any time soon.

>>> At the moment we're concentrating on arm5tel as it works
>>> and we need to get Fedora 14 and rawhide there and its the combination
>>> that can support the broadest amount of hardware, one that's on the
>>> road to completion people can and will start looking at a version
>>> optimised for newer more power HW. Its only in the last week or so the
>>> team have managed to get enough of F-13 built to be able to compose a
>>> rootfs for testing it.
>> Ooo! Any chance of a link to this rootfs and the F13 arm5tel yum repository?
> 
> It was on planet Fedora in the last week or so posted by Paul W (of
> Fedora ARM fame @ Seneca college). It might be linked on the Fedora
> ARM wiki page too (sorry, don't have my browser history to hand).

Thanks, that was enough to find it. :)
http://paulfedora.wordpress.com/2010/12/15/fedora-13-arm-alpha-root-file-system/

Gordan


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