[U-Boot] [U-Boot, 1/2] common: Add CCACHE variable to allow use of ccache

[Marek Vasut]

Dear York Sun,

> On 08/22/2013 12:36 PM, Marek Vasut wrote:
> > There is an env variable to configure separate ccache cache dir , so just
> > by setting that. But then , when each build ends, you would need to
> > clean it up somehow. It was mentioned in the discussion with the patch.
> > You can try working on this some more and post a patch, then we can talk
> > about further forging of this.
> 
> I fixed the 2nd patch and I am running MAKEALL with individual board
> folder for ccache. The compiling time for the first run on my laptop is
> 56 minutes. The 2nd run is 23 minutes. About the same improvement if
> using a big unified cache for all boards. By the way, each board cache
> is about 7~8MB.
> 
> You set my expectation high. I was hoping to get 10x or more improvement.

It should be more, try checking if there is no bottleneck.

Best regards,
Marek Vasut