[Xenomai-core] [RFC] tame the watchdog (was: Beginner's question / testsuite / latency)

[Jan Kiszka <jan.kiszka@domain.hid>]

[-- Attachment #1: Type: text/plain, Size: 909 bytes --]

Philippe Gerum wrote:
>> Still, reinitializing X while the latency test runs causes
>> the latter to hang, albeit LOC is still flowing properly and the box
>> keeps going normally.
> 
> This one was due to the nucleus watchdog which triggered right after the
> graphic mode was fully initialized, due to the huge amount of
> unpreemptible time spent doing this; this caused the sampling task to be
> detected as a runaway thread. So the behaviour is ok, albeit a bit
> frightening at first.
> 

That reminds of the unfortunate characteristics of the 2.6 oom-killer:
unless you set your time-critical app's oom_adj to -17, you are never
really safe from being killed accidentally on low-mem scenarios.

What about introducing some mechanism to protect audited tasks against
the watchdog? A simple thread flag settable via existing APIs, ignored
if there is no watchdog compiled in?

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]