[oe] [PATCH 2/6] conf/bitbake: improve compression image handling

[Otavio Salvador]

On Fri, Apr 8, 2011 at 09:18, Phil Blundell <philb at gnu.org> wrote:
> There is a bit of a tradeoff for gzip, though I'm not sure you would
> notice it on modern hardware.  For bzip2 it's more significant; if
> you're bzipping large files (several GB) then the choice between -9 and
> -1 is quite noticeable even on a relatively powerful cpu.  I'm not sure
> you'd notice much difference with either gzip or bzip on a 32MB jffs2
> image.

It is noticible; I am doing images for some quite slow machine and it
does matter otherwise I wouldn't have done it.

> And for unzipping, my recollection is that the decompressor stages of
> both gzip and bzip run in more-or-less constant time irrespective of the
> settings that you used when compressing.
>
> So yeah, I agree, it isn't obvious that there is going to be much
> real-world benefit from tweaking these knobs for gzip and bzip2.  If
> someone wants that ability then fine, but ideally in a way that doesn't
> cause further metadata bloat for everyone else.  One obvious way to do
> that would be to put the default variable settings in the
> image-generating classes, rather than in bitbake.conf, so that they
> don't get set at all for the majority of recipes if you are happy to
> accept the defaults.

I agree its place is on the image class or another; this doesn't
matter too much to me if I have a place to change it.

-- 
Otavio Salvador                             O.S. Systems
E-mail: otavio at ossystems.com.br  http://www.ossystems.com.br
Mobile: +55 53 9981-7854              http://projetos.ossystems.com.br