Re: packages 2020Q4

[mlelstv%serpens.de@localhost (Michael van Elst)]

gdt%lexort.com@localhost (Greg Troxel) writes:

>  would using the v6 packaege build be slower in a measurable sense than
>  using the v7 packages?

Some packages are slower with v6 code, but on average there isn't
much of a difference.

Example for a RPI2 (v7 hardware, running v6 userland):

v6 package:

% time digest sha512 /netbsd
SHA512 (/netbsd) = f82a35dce57ea0a80cea3d8fb2022e6deacac8e23139dc1372cd5329b967c70f2de16ef613f0a7ff833168e98fae28b1eb0949d7a210e0259d8eec5537abea96
1.368u 0.050s 0:01.68 83.9%     0+0k 0+0io 0pf+0w

v7 package:

% time digest sha512 /netbsd
SHA512 (/netbsd) = f82a35dce57ea0a80cea3d8fb2022e6deacac8e23139dc1372cd5329b967c70f2de16ef613f0a7ff833168e98fae28b1eb0949d7a210e0259d8eec5537abea96
1.270u 0.078s 0:01.50 89.3%     0+0k 0+0io 0pf+0w

The digest program uses its own hash routines, the common (v6-built) libc
in both cases doesn't matter.


>  Is the v6 package set missing packages compared to v7?

Currently 21519 packages build for v6 and 21632 for v7.

To some degree that's just unstable builds (the next attempt of a
failed build might be successful).

Then you have packages that do not recognize evbarm6hf, but would
build with adapted configure scripts or patched #ifdefs.

A small number of packages just do not support earmv6hf because
they include assembler code only for earmv7hf. You would need to
port them.


>I'm guessing the answer is that it makes sense to use v7 packages on
>v7-capable machines, but the answer is not yet in the RPI howto, so I
>can add it if there is consensus/rationale.

The packages are tagged with the architecture, so you need to force
installing earmv7hf packages on a system that is built as earmv6hf.

The primary decision is whether to run a system built for earmv6hf or earmv7hf.
If you have mixed systems (e.g. RPI0/RPI1 and RPI2/3) using earmv6hf for all
might have advantages.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."