Messages in this thread |  | | Date | Tue, 23 Nov 2004 10:21:52 +0100 | | From | Ingo Molnar <> | | Subject | Re: Priority Inheritance Test (Real-Time Preemption) |
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* john cooper <john.cooper@timesys.com> wrote:
> >>I'd hazard a guess the reason existing implementations do not do this > >>type of dependency-chain closure is the complexity of a general > >>approach. [...] > > > > > >please take a look at the latest patch, it is i believe handling all the > >cases correctly. It certainly appears to solve the cases uncovered by > >pi_test. > > Yes I see where you are walking the dependency chain > in pi_setprio(). But this is under the global spinlock > 'pi_lock'. > > My earlier comment was of the difficulty to establish fine > grained locking, [...]
the issues raised in the paper and in this thread were much more fundamental than SMP-scalability. Considering the costs of a hard-RT mutex approach itself i dont think SMP-scalability is a primary issue right now.
> [...] However I'd offer there is more concurrency possible in this > design.
yeah, most likely - but correctness comes first. SMP scalability is something that can be done later.
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