On 06/10/2011 11:26 AM, wenzong fan wrote:
-------- Original Message --------
On Thu, 2011-06-09 at 15:40 -0700, 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.
There is a little more detail on:
https://wiki.yoctoproject.org/wiki/Yocto_1.1_Schedule
Specifically, "c) Set CCACHE on a per recipe basis. need to figure out
whether ccache data can be shared and under what circumstances."
so something like adding:
export CCACHE_DIR = "${TMPDIR}/ccache/${TARGET_SYS}/${PN}"
I think that set CCACHE_DIR on per recipe basis would degrade hit efficiency,
the following ccache data can be shared if they they use the same CCACHE_DIR,
but if we set CACHE_DIR on a per recipe basis, then they can't be shared:
1) Most pkg's configure will run "gcc foo.c" for checking the C compiler,
these compiling are the same between different pkgs at most time.
2) Some recipes' compiling are similar, for example: gcc-cross,
gcc-corss-initial and gcc-cross-intermediate.
I think that:
export CCACHE_DIR = "${TMPDIR}/ccache/${TARGET_SYS}/"
would be better.
// Robert
to bitbake.conf with a bit more thought into working out the right
components to add to the variable.
Cheers,
Richard
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