Messages in this thread | | | Date | Thu, 7 Jul 2005 11:49:39 -0700 (PDT) | From | William Weston <> | Subject | Re: Real-Time Preemption, -RT-2.6.12-final-V0.7.51-06 |
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On Thu, 7 Jul 2005, Ingo Molnar wrote:
> > Still looking into this issue on -51-06. Found something really odd: > > SCHED_NORMAL tasks will start to inherit the priority value of some > > other SCHED_FIFO task. If JACK is started at a given SCHED_FIFO > > priority, X and all of its children will inherit the same priority > > value after login. Other random processes will inherit this, too -- > > sometimes init... > > > > SCHED_NORMAL tasks suddenly inheriting priority values in the range > > normally reserved for SCHED_FIFO could explain at least part of the > > meltdown I've been seeing. Any thoughts? > > is this inheritance perpetual? It is normal for some tasks to be boosted > momentarily, but if the condition remains even after jackd has exited, > it's clearly an anomaly. (lets call it "RT priority leakage".) Priority > leakage on SMP was fixed recently, but there could be other bugs > remaining.
Yes, this leakage perpetual. That's what struck me as odd.
> There's priority-leakage debugging code in the -RT kernel, which is > activated if you enable CONFIG_DEBUG_PREEMPT. This debugging code, if > triggered, should produce 'BUG: comm/123 leaked RT prio 123 (123)?" type > of messages. But ... due to a bug it would not print out anything but > would lock up hard if it detects the condition (and if > RT_DEADLOCK_DETECT is enabled). I have fixed this reporting bug in the > -51-08 kernel.
-51-08 is building now. I'll check out the latest, too.
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