[Pkg-raspi-maintainers] Building an image of Debian for Raspberry Pi 3

[Ludovic Brenta]

On Thu, 26 Apr 2018 16:06:17 +0200, Michael Stapelberg wrote:
>> - ext2 instead of ext4 for the root partition (SD cards are slow
>>   and do not need a journalling file system which would only slow
>>   them down even more, I think).
>
> Do you have any benchmarks/measurements supporting this claim? This
> is the first time I hear about it.

I have no benchmarks but I know that a journal must be written to
*in addition to* the regular file data and meta-data.  This not only
uses additional bandwidth (which is not normally noticeable on a
6 Gbit/s link like SATA-3 but may be on USB 2.0 or SD card) but also
creates a hot-spot on the device containing the journal (and this is
probably bad for low-end devices like an SD card).

>> The other change is that python3.6-minimal has been upgraded from
>> 3.6.4-3 in your latest image to 3.6.5~rc1-1 (testing) and 3.6.5-3
>> (unstable).  And this package is giving me the following
>> headache:
>>
>> qemu: uncaught target signal 11 (Segmentation fault) - core dumped
>>
>> while executing the post-installation script of python3.6-minimal.
>> As a consequence, all subsequent invocations of apt install will
>> also fail as they notice the package is unconfigured and
>> re-execute
>> the postinst script.
>>
>> I think this may be due to the lack of support for threading in
>> qemu, combined with the use of pipes in the postinst script.
>
> I would be surprised if qemu did not support threading. Have you
> searched for bug reports about this symptom?

Yes and I found these:
http://qemu.11.n7.nabble.com/Uncaught-target-signal-11-Segmentation-fault-core-dumped-tp290467p290775.html
https://stackoverflow.com/questions/15086238/error-qemu-uncaught-target-signal-11-segmentation-fault

but I realize thay they may be outdated now. I was also led to
understand that qemu did not support threading for ~10 years,
maybe this has finally been implemented since.

Also, no bug reports specifically for my problem.  And I am not
yet certain this is a bug so I wanted to ask you before I filed one.

-- 
Ludovic Brenta.