[meta-freescale] [meta-fsl-arm PATCH 01/23] fsl-dynamic-packagearch.bbclass: Dynamically set package architecture

[Otavio Salvador]

On Mon, Sep 23, 2013 at 8:04 PM, Eric Bénard <eric at eukrea.com> wrote:
> H Otavio,
>
> Le Mon, 23 Sep 2013 16:55:36 -0300,
> Otavio Salvador <otavio at ossystems.com.br> a écrit :
>
>> This allow to easy reuse of binary packages among similar SoCs. The
>> usual use for this is to share SoC specific packages among different
>> boards. The class can be used to share GPU packages for i.MX53 boards
>> (as all them share the AMD GPU) and i.MX6 based boards (as all them
>> share Vivante GPU).
>>
>> It inspects the database and identify if the package provides or
>> depends on one of subarch provided values and if it does, it sets the
>> PACKAGE_ARCH for MACHINE_SUBARCH value otherwise if it matches in the
>> machine specific filter, it sets it to MACHINE_ARCH.
>>
>> Change-Id: Icb0a8060e862c8eeb166c45d1b39c40de07b01d8
>> Signed-off-by: Otavio Salvador <otavio at ossystems.com.br>
...
> what is the time cost of this dynamic setting vs the static one ?

This reduces the amount of packages we build, for example in case of
core-image-x11 we:

$ ls -l tmp/deploy/rpm/cortexa9hf_vfp_neon_mx6/*.rpm | wc -l
75

So we reuse 75 binaries; these would be build otherwise.

Regarding it being dynamically set or statically set it has following benefits:

* correctness: it is easier to ensure the system behaves as expected
* correctness for non-tracked recipes: new recipes, if depending on
virtual/kernel or GPU has the right architecture choosen, without a
.bbappend file for them
* safeness: non-expert users get a more adequate behavior as the
complexity of choosing the right architecture is simplified for them
* easy maintenance: it is easier for me, as maintainer, to maintain a
code which decides what to do than having hundreds of bbappend files
for it

I hope it justify it enough.

Regards,

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750