Messages in this thread | | | Date | Fri, 18 Mar 2005 17:02:29 +0100 | From | Ingo Molnar <> | Subject | Re: Real-Time Preemption and RCU |
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* Bill Huey <bhuey@lnxw.com> wrote:
> I'd like to note another problem. Mingo's current implementation of > rt_mutex (super mutex for all blocking synchronization) is still > missing reader counts and something like that would have to be > implemented if you want to do priority inheritance over blocks.
i really have no intention to allow multiple readers for rt-mutexes. We got away with that so far, and i'd like to keep it so. Imagine 100 threads all blocked in the same critical section (holding the read-lock) when a highprio writer thread comes around: instant 100x latency to let all of them roll forward. The only sane solution is to not allow excessive concurrency. (That limits SMP scalability, but there's no other choice i can see.)
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