Approach to system testing for Osmocom stack

[Holger Freyther]

> On 4. Feb 2018, at 22:35, Holger Freyther <holger at freyther.de> wrote:

Hi,


> * SIGCHLD arrives
> * Something will be written into one end of a socketpair[1]
> * In the python code on wait(2) will be called on every registered process
> (https://github.com/python/cpython/blob/3.6/Lib/asyncio/unix_events.py#L819)


there is a way to switch to a child reaper that is using wait(-1.. but even
then we have two issues.

1.) If I use await asyncio.create_subprocess_exec... then we can't tick
with 50ms. On a 60s schedule to start 10k processes there is a delay of +60s.

2.) If I delay the process creation then I can almost keep the schedule most
of the time but we run into buffering exceptions and/or not all tasks are
started within a reasonable amount of time.

Knowing what I know now I would have gone for Go. It is made for the kind of
concurrency where python seems unusable. I hesitated to build my own event
loop but will build something that looks like our C apps in python (single
select, no async/await).

holger