[nptl] NPTL issue with pthread_attr_setsched{param|policy}

[Loic Domaigne <loic-dev@gmx.net>]

Hello,

I apologize if I report a known BUG to you. I remember seeing a related 
issue on the NPTL Forum, but I am not sure if it is exactly that one. 
(And, of course, I am too lazy to check it by myselves).

I have just answered a question on c.p.t. that led me to write a small 
program which creates a thread in the SCHED_RR scheduling class at a 
given priority using thread's attribute.

With LinuxThreads, it works as expected. If the process is not started 
as root, pthread_create() failed (due to wrong permission). If it is 
executed as root, the RT-thread preempts the SCHED_OTHER threads.

However, with NPTL (v0.61) none of the two above cases behave as 
expected. When the process is not started as root, pthread_create() 
succeeds, but the RT-thread seems to run in the SCHED_OTHER class. This 
should failed. When the process is started as root, the RT-threads run, 
but apparently in the SCHED_OTHER class. This should run in the SCHED_RR 
class.

Do you have already tracked down that NPTL specific BUG already?
Otherwise, I would be _really_ happy to devise a test.


With Regards,
Loic.
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