[yocto] Accelerate kernel module built in eSDK?

[richard.purdie at linuxfoundation.org]

On Fri, 2018-12-28 at 22:35 +0800, Zhaolong Zhang wrote:
> On 2018/12/28 19:40, richard.purdie at linuxfoundation.org wrote:
> > On Fri, 2018-12-28 at 18:19 +0800, Zhaolong Zhang wrote:
> > > Hi Experts,
> > > 
> > > Building out-of-tree kernel modules in eSDK will trigger a new
> > > rebuilding of kernel, which consumes lots of time.
> > > Is it possible to cache the do_shared_workdir() task in sstate-
> > > cache
> > > and ship it within eSDK? And how?
> > > 
> > > Or is there other method to accelerate?
> > > 
> > > Thanks in advance.
> > 
> > It is possible but it means creating a tarball of all the kernel
> > source
> > and build artefacts. Usually its just as quick to extract new
> > kernel
> > source and build it than it is to store this and extract it. The
> > sstate
> > object would be huge.
> > 
> 
> Hi Richard,
> 
> Thanks for responding!
> 
> Isn't sstate object also a tarball for them? Creating another
> tarball 
> would be a hacking and how can I let module.bbclass know that the
> kernel 
> source and build artifact are ready, without sstate hashes?

My point is that using sstate for this will be slow and mean there is a
very large sstate object. The performance benefits aren't very clear.
We used to create an sstate object but it got a lot of complaints about
speed/performance.

Cheers,

Richard