[fedora-arm] Fedora 20 for Raspberry Pi????

Richard W.M. Jones rjones at redhat.com
Wed Jan 1 11:50:29 UTC 2014


On Wed, Jan 01, 2014 at 10:22:29AM +0000, Gordan Bobic wrote:
> On 01/01/2014 10:18 AM, Richard W.M. Jones wrote:
> >On Mon, Dec 30, 2013 at 10:27:38PM +0800, Andy Green wrote:
> >>Yeah I think until you realize why and how it's a problem (in other
> >>words, you got bitten) most programmers wouldn't particularly think
> >>to defend against it because the code is c-legal and works on x86.
> >
> >That's because it *isn't* a problem.
> >
> >We shouldn't worry about misalignment problems in Fedora ARM unless
> >you can demonstrate with hard numbers that a particular misalignment
> >causes a performance issue.
> >
> >Set alignment to fixup, and forget about it.
> 
> How dare anyone suggest the developers be educated and the problem
> be fixed rather than worked around.

There's nothing to educate about.  It's a non-problem except in a
narrow performance case.

Most developers don't need to worry about swap, for precisely the same
reason.  Alignment fixups, swapping, cache lines, TLBs, huge pages, ...
are details of the implementation, and you don't need to think about
them unless you're chasing a performance problem.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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