[Openembedded-architecture] Switch sstate and other pieces of the project to xz?

[Khem Raj]

On Sat, Jan 9, 2016 at 8:48 AM, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
> Times change and xz is becoming the defacto compression format and
> utility. It has better compression ratios than gz and similar
> compression/decompression times. Its better than bzip2 decompression in
> particular.
>
> Given the bzip2 lack of performance, switching to xz for the SDK
> appears to be an easy winning change.
>
> Switching sstate over to xz may be a little more controversial and
> invasive, not least that we'd need to update the docs to mention the xz
> dependency.
>
> Equally, I think I'm coming down strongly in favour of switching. DOes
> anyone have any concerns about that?
>
> There are no compatibility of sstate feed issues, objects just change
> name at some point and the old and new can coexist side by side if
> needed.
>
> [NB: I know that some have proposed making sstate compression format
> configurable. I still have mixed feelings about that, not least that it
> encourages differences in a part of the system I'd prefer to try and
> keep standardised and figure out the best selection. In this case, xz
> does look like a clear winner over gzip]

I think its fine idea.May be we can top it up with pxz[1] to harness multicores
and also use xz as default for source archive generation as well.


-Khem