Neon enablement in qt for raspbian.
Back when Mike and I founded raspbian, there was only the pi1. Packages
that used neon often set off our armv7 contamination checker and at the
time we saw neon support in raspbian as at best a pointless waste of
space and at worst a problem, so we simply disabled it wherever we ran
into it.
However times have changed. The raspberry pi 2 and 3 have been released
and Raspberry Pi want to continue shipping a single image for all their
products for the forseable future.
As a result I am currently working on re-enabling neon in raspbian where
appropriate. I have been doing the work in raspbian jessie and intend to
forward port it to raspbian stretch later. Clearly since we still
support the original raspberry pi and the new pi0 only packages with
correctly functioning neon runtime detection are candidates for neon
enablement.
There are two qt source packages in raspbian jessie where we currently
have neon disabled. qt4-x11 and qtbase-opensource-src . I have a couple
of questions.
1: are these packages supposed to have runtime neon detection (either in
the packages own code or through ld.so hwcaps).
2: For each of the packages can anyone suggest a simple benchmark/test
that will hit the neon codepaths which I can use to check that neon
detection is doing it's job (i.e. that the package still works on the
pi1 and there is a performance improvement over the package without neon
on the pi2)
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