Re: [Dragora-users] Proposal: add to qi possibility to switch type of tarlz compression granularity

[DustDFG]

Hello!

On Wed, May 18, 2022 at 9:03 PM Matías Fonzo <selk@dragora.org> wrote:
>
> El 2022-05-17 03:04, DustDFG escribió:
> > Hello!
> >
> > I want to know why you use tarlz. If I right understand, you use tarlz
> > archive format (not usual tar.lz or something else) because it has
> > multi-threaded facilities. Am I right?
>
> Not only for the multi-thread capabilities, which speeds up the checking
> of a tarball when testing it, there are a number of reasons, one of them
> is that tarlz creates a more secure format than the one proposed by
> POSIX pax format; tarlz is based on the lzip format, its inclusion is a
> decision that was made for Dragora in 2008.  Now expanded elsewhere, it
> is the only reliable format that I know of.
>
> > I read the source code of qi and found that qi uses tarlz with option
> > --solid. It means that tarlz can't unpack this archive with using
> > multi-threading [1] [2].
>
> This does not mean that it can be done in the future, I understand that
> it is not easy to implement.  Beyond implementation, --solid is the
> recommended option for packages, as it is the final product.
>

I am not sure that it is difficult to implement. We can just create
variable tarlz_compression_granularity
and and use it instead of --solid. I propose something like this:

tarlz_compression_granularity="--solid" or
tarlz_compression_granularity="--no-solid"

...

( umask 022 ; tarlz $tarlz_compression_granularity -9 $tarlz_opts -cvf - -- * )


> > I understand that you want to get the
> > smallest possible size of an archive. If I have a fully empty disk
> > with 1TB capacity, I may want to get more speed especially if I build
> > packages for testing (not for release)...
>
> And this has been optimized in Dragora, not to mention that it is also
> subject to build systems, hardware, parallel jobs for the compiler....
>

I am not sure that I understood it correctly. As I know, qi waste some
time at build time. When I want to build package and install it for
example with the following command `qi build -i`, qi produces the tlz
package and then installs it (unpack). It is visibly when you build
kernel package....

> > I want to propose you to add to qi possibility to point compression
> > granularity level through new option or maybe through qirc file. Note:
> > I don't propose to change default compression granularity level. I
> > simply want to have a possibility to change it when I want it.
> >
> > [1] https://www.nongnu.org/lzip/manual/tarlz_manual.html#Introduction
> > [2]
> > https://www.nongnu.org/lzip/manual/tarlz_manual.html#Multi_002dthreaded-decoding
>
> Let's see what our friend, the author, has to say.  :-)
>

Do you talk about the author of tarlz? (Antonio Diaz Diaz)