On Sat, 31 Dec 2022 at 09:59, Roberto A. Foglietta <roberto.foglietta@gmail.com> wrote:
>
> Hi all,
>
>  sorry for the image but some numbers should be displayed in a proper
> form. I continued to work on the building optimization of ISAR and the
> results are quite interesting. Almost 2x with some great achievements
> in some specific areas like cache reduction (22x) or in some
> particular cases like using a little of the repository downloaded
> which brings to a disk usage reduced by 11x times. About building
> time, the ratios are a little under-estimated because network
> downloads for debootstrap and apt update take a fixed time that cannot
> be reduced. My first tests indicate that also custom debian packages
> and repackaged .deb are correctly deployed into the system despite the
> changes. More tests are welcome.
>

Dear all,

my personal fork was broken in some ways for some time but today, I completed the first round of rebasing and finally it is up again.
These are the numbers, formatted in HTML for a nice reading and an image attached as well.

From these numbers the first thing we notice is that the size of the deb cache
does not matter at all because 10x more is not slower at all. This makes per-
fectly sense because linking 385 or 1260 does not make such a difference.
       
          full debs           minimal           rebnext
       ------------ basic-os -------------- ==============
        3498 Mb (max)   |  3489 Mb (max)     1.00x   1.00x
        2588 Mb (rest)  |  2587 Mb (rest)    1.00x   1.00x
        3417 Mb (deb)   |   364 Mb (deb)     9.39x
         814 Mb (wic)   |   814 Mb (wic)      -
         273 Mb (cache) |   273 Mb (cache)   1.00x
       time: 3m09s      | time: 3m10s        2.58x
       
Compared to the original the performances increase is impressive, in both cases:

          original           cherries + schroot + rebase
       ------------ basic-os -------------- ==============
       43954 Mb (max)   |  3498 Mb (max)    12.57x  16.07x
       26548 Mb (rest)  |  2588 Mb (rest)   10.26x  14.50x
        3741 Mb (deb)   |  3417 Mb (deb)      -
         820 Mb (wic)   |   814 Mb (wic)      -
       11789 Mb (cache) |   273 Mb (cache)  43.18x
       time: 8m33s      | time: 3m09s        2.71x

          original           cherries + schroot + rebase
       ------------ complete ------------- ===============
       52507 Mb (max)   | 28606 Mb (max)     1.84x   2.23x
       43311 Mb (rest)  | 19413 Mb (rest)    2.23x   3.33x
        3741 Mb (deb)   |  3417 Mb (deb)      -
        9159 Mb (wic)   |  9155 Mb (wic)      -
       11799 Mb (cache) |   283 Mb (cache)  41.69x
       time: 20m13s     | time: 11m44s       1.72x

Considering that the local .deb cache growing with the time because new updates
will be added, and comparing the performance gains between the basic-os and the
complete image, we can say that on the long run also the complete case will
reach the 2x of performance at least in time building.

Best regards, R.