[OE-core] [Yocto] The design document for ccache-native

[Khem Raj]

On 06/09/2011 04:51 PM, Tom Rini wrote:
> On 06/09/2011 03:40 PM, Saul Wold wrote:
>> On 06/02/2011 08:11 PM, wenzong fan wrote:
>>> Hi Folks,
>>>
>>> Please help me to review the design document for ccache-native, and
>>> I also have two questions about it, any answers or suggestions are
>>> appreciated.
>>>
>>> * Feature name: ccache-native
>>>      Priority: P3; M2
>>>      Owner: Wenzong Fan
>>>      Summary: Integrate ccache-native to yocto
>>>
>>> * Description:
>>> Bitbake supports the 'CCACHE Mechanism', but 'ccache' hasn't been
>>> included by poky/yocto, just add it as a native tool.
>>>
>>> * Usage:
>>> Build ccache as a native tool by default and enable it for speeding
>>> target packages build.
>>>
>>> * Implementation:
>>> 1) Copy bb file from OE upstream to:
>>>        meta/recipes-devtools/ccache/
>>>
>>> 2) Update bb file to get the latest ccache_3.1.5 and split the single
>>> bb file to:
>>>        'ccache_3.1.5.bb', 'ccache.inc'
>>>
>>> 3) Enable ccache in the native tools building.
>>>
>> You will need to have it be a dependency pretty early on in the build.
>> Additionally, this is a bit a new part to this task, we want to have the
>> default CCACHE_DIR for the build default to a directory in TMPDIR
>> instead of the user's home directory.  This will mean setting an
>> environment variable somewhere early also.
>
> Can we instead veto ccache and remove it from the bitbake docs?  I can't
> count the number of times I've run into what I can only imagine are
> ccache conflicts to explain why a random build failure with ccache in use.
>

It works on some hosts somewhat reliably and is unpredictable on some as 
you say. I think keeping it optional is probably the right thing but 
making it default may not be a good thing.