rtprio and kse

[eischen at vigrid.com (Daniel Eischen)]

On Mon, 30 Jun 2003, Petri Helenius wrote:

> > 
> > Theoretically any process with rt priority can monopolise the CPU if it
> > spins, regardless of whether it's threaded or not..
> > 
> > Is not that what having RT-priority means?
> 
> Yes, but in non-threaded environment with multiple processes
> competing for CPU libc is not expected to have locks. In threaded
> environment it does have them around things like malloc. My concern
> is the realtime thread spinlocking waiting for a lock which is held 
> somewhere which does not get scheduled. These locks are not 
> visible to the appliation and thus one must either put additional
> mutexes around them or know that libc stuff is rtprio-thread-safe.

Libpthread silently converts libc spinlocks into non-spinning
locks; there should be no deadlock or starvation issues in
userland.  I don't know if libthr ans any issues with spinlocks
or not.

-- 
Dan Eischen