Re: AW: L4_ThreadSwitch behaviour

Ben Leslie wrote:
> On Fri Feb 16, 2007 at 11:30:17 +0100, Christian, Martin, OPEE45 wrote:
>> Hi Ben!
>> Now it's working! :-) I've changed two things:
>> a) I'm using a loop for time slice donation
>> b) I'm setting the prioriy of the Pager to 0xff (the same as roottask)
>>
>> I assume after the Pagefault IPC was created, the Scheduler is run to select the next runnable thread - which is roottask. Thus the Pager is never executed.
>>
>> But that seems unfair to me! Ping thread got donated a time slice but can't ever use it. Just because it creates a Pagfault at startup and thus sending an IPC is required, which in turn triggers the scheduler. But I suppose, that's life ... :-/
> 
> Getting scheduling right with timeslice donation is quite tricky, and
> probably best avoided.

Hi Christian, Hi Benno,

this paper:

http://www.ertos.nicta.com.au/publications/papers/Ruocco_06.abstract.pml

explains a fair bit of L4 [Pistachio/N1/...] scheduling, including the tricky 
timeslice donation. Have a look and let me know if you need more clarifications.

	Sergio

-- 

--

http://www.cse.unsw.edu.au/~sruocco/
ERTOS Researcher                                              Lecturer
National ICT Australia Ltd.              University of New South Wales

This email and any attachments are confidential. They may contain
legally privileged information or copyright material. You should not
read, copy, use or disclose them without authorisation.  If you are
not an intended recipient, please contact us at once by return email
and then delete both messages.  We do not accept liability in
connection with computer virus, data corruption, delay, interruption,
unauthorised access or unauthorised amendment.  This notice should not
be removed.

begin:vcard
fn:Sergio Ruocco
n:Ruocco;Sergio
email;internet:[email protected]
version:2.1
end:vcard