Re: Thread starvation with mutex

Jamie Lokier <[email protected]> Fri, 13 Feb 2004 23:52:28 +0000
Newsgroups gmane.comp.lib.phil
Message-ID <[email protected]>
David L wrote:
> Without the RTNPTL patch, is NPTL missing complete support for priority 
> scheduling using SCHED_FIFO or is it just missing some of the more subtle 
> real-time scheduling features such as priority inheritance?

I admit I don't know much about the RTNPTL implementation, but having
thought about scheduling issues due to the other recent threads on
phil-list, I see that real-time futex wakeups would _not_ guarantee
that a SCHED_FIFO task would ever acquire a mutex which SCHED_OTHER
tasks were periodically releasing.  (Think about multiple CPUs).

In other words, even _with_ RTNPTL it's not clear that you get
"complete support for priority scheduling using SCHED_FIFO" - that
depends on what you _mean_ by that phrase.

If you can elaborate what exactly you mean, then we can address the
question accurately.

-- Jamie