Messages in this thread | | | Date | Tue, 03 Aug 2010 05:42:16 -0600 | From | "Gregory Haskins" <> | Subject | Re: periods and deadlines in SCHED_DEADLINE |
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Hello Peter, Steven, Thomas, et al. !
Its been a while.
>>> On 8/3/2010 at 04:16 AM, in message <1280823360.1923.419.camel@laptop>, Peter Zijlstra <peterz@infradead.org> wrote:
[snip]
> > So we replace the global lock with cmpxchg like loops using 2 per-cpu > locks. Our current SCHED_FIFO balancer does just this and is found to be > a very good approximation of global-fifo (iirc there's one funny case, > but I can't remember, maybe Steve or Gregory can remember the details).
The only thing I remember at the moment is that Steven and I found one last remaining bug in an extreme corner case where priority order may be violated. Sadly, I can no longer recall the exact specifics and would have to dig into the code to remember. The good news is I believe the issue is fixable. Its just a matter of impl+test, which neither of us ever seem to have found the time to properly dedicate. Perhaps this will be the catalyst ;)
-Greg
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