[mkc2007] Justifying a Halt Systemcall

[Emanuel Thomas]

Marcus Voelp wrote:
> Hi,
> yesterday in the lecture we discussed whether it makes sense to
> introduce systemcall to halt and resume a thread respectively to resume
> threads on pending sends. The quick answer I gave in the lecture was
> that these are "easy" to understand and "easy" to implement systemcalls
> and thus a good exercise. However, technical arguments for or against
> these systemcalls we did not discuss. [...]
> The questions are therefore:
> - do we need such a systemcall?

I don't think so.
If we want to sleep and someone will wake us up, this can also be done via
IPC.
If we want to resume, when someone is sending us an IPC, we could just do
an open wait which has the same effect.