What does idle thread do

Adam Lackorzynski adam at os.inf.tu-dresden.de
Sat Sep 27 11:24:09 CEST 2014

On Fri Sep 26, 2014 at 13:52:12 -0400, Yuxin Ren wrote:
> Thank you very much.
> I have a further question.
> The idle thread creates another two threads--sigma0_thread and boot_thread
> (in Kernel_thread::init_workload in kernel_thread-std.cpp file ).
> I am curious about what their priority is and when they finish.

Their priority at creation time is 1, and they never finish, as those
are the sigma0 and moe threads.

> In addition in my test, I only have a single thread doing memory map and
> unmap.
> But I find it is always preempted by another two threads. I do not know
> what they are.
> Could you give me some hints?

I suggest do use context switch logging to find out.
Use shift-O in jdb, toggle "Context switch" to on, let the system run,
enter jdb again, look at trace with shift-T.
You need to have extended logging enabled in Fiasco's config.

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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