Re: [PATCH linux-2.6.13-rt14] Priority inversion bug

[Ingo Molnar]

* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Tue, 20 Sep 2005, Ingo Molnar wrote:
> > thanks - added it to my tree. I'm wondering why it never showed up in
> > practice?
> 
> How do we know if it hasn't?  It wouldn't bug, you may just have a 
> longer latency on the higher priority process than what should be. It 
> did happen on my kernel, and the way I found that it did, was that I 
> had a test in the passing of ownership to make sure that the one that 
> got the lock is indeed the highest priority process. Without this 
> check, we probably would never know.

'showed up' as in 'clearly incorrect scheduling shown in latency trace'.  
It's probably the complex locking scenario that never made it trigger in 
the simpler tests that e.g. rtc_wakeup or other latency testers do.

	Ingo
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