[yocto] configure optimization feature update

[Esben Haabendal]

On Wed, 2011-06-15 at 18:28 -0700, Khem Raj wrote:
> On Wed, Jun 15, 2011 at 5:57 PM, Xu, Dongxiao <dongxiao.xu at intel.com> wrote:
> > Hi Richard,
> >
> > Recently I was doing the "configure optimization" feature and collecting data for it.
> >
> > The main logic of this feature is straight forward:
> >
> > 1. Use the diff file as autoreconf cache. (I use command: "diff -ruN SOURCE-ORIG SOURCE", here "SOURCE-ORIG" is the source directory before running autoreconf, while "SOURCE" is the directory after running autoreconf).
> > 2. Add SRC_URI checksum for all patches of the source code.
> > 3. Tag each autoreconf cache file with ${PN} and the SRC_URI checksum of source code and all patches.
> > 4. If the currently SRC_URI checksum matches the cached checksum, then we can patch the cache instead of running "autoreconf" stage.
> >
> 
> The autoconf'ing is sort of arbitrary at the moment. Depending on what
> is staged the results may vary.

Which can be properly fixed by using per-recipe (per-workdir) staging.

/Esben