On Thu, Dec 26, 2013 at 07:49:58PM +0000, Gordan Bobic wrote:
On 12/26/2013 02:20 PM, Derek Atkins wrote:
>Gordan Bobic <gordan(a)bobich.net> writes:
>
>>(e.g. (but not limited to) a large number of packages make little or
>>no effort to ensure memory accesses are aligned - including the likes
>>of e2fsprogs, and transparent alignment fixup in hardware is only
>>available on armv7 and later).
>
>I'm surprised that Ted isn't willing to fix issues in e2fsprogs.
>
>If you can point me to the upstream bug reports I can ping him to see
>what's up?
Take a look here:
http://comments.gmane.org/gmane.comp.file-systems.ext4/33324
As has been mentioned before, there is a whole shedload of packages
that have similar issues - I have seen literally thousands of
alignment faults get reported (I have the alignment set to fix+warn
on my armv5tel builders) in various packages during build and test
stages. Once upon a time I planned to collate the data and get the
issue reported to all upstream maintainers, but that is a mammoth
task just to report, let alone fix, and I have very little faith
there is enough will among the developers to fix all the affected
packages and ensure they write code that isn't affected by this
problem going forward.
I disagree that it is even a problem; except in a very small number of
cases where it causes a measurable slowdown. Is there a way to find
out if a program is doing an excessive number of alignment fixups?
Basically this is an architectural problem in ARM, and not something
developers should go through hoops to fix except in the tiny number of
cases where it causes an actual, measurable problem.
Rich.
--
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