Re: SCHED_FIFO and SCHED_RR broken by cfs

[Peter Zijlstra <peterz@infradead.org>]

On Mon, 2008-08-18 at 21:24 +1000, Nick Piggin wrote:

> Really, you think the enterprise distros will willingly break POSIX
> and their own backwards compatiblity by default? I wouldn't have
> thought so, but anyway I guess they are free to make that choice, so
> where's the problem?

I'm not seeing why you're making such a big fuss over this - IMO its not
such a significant breakage. Esp since very few realtime apps will
require such large amounts of time to ever run into the throttle.

If their usage is 95%+ cpu they must have magic WCET estamates - or like
in this case, be a benchmark app which IMHO just abuses the real-time
class.

It's like running your real-time code on a 5% slower cpu - if it runs
correctly on the 5% slower cpu, it will run correctly here too.

Note that correctness from a RT pov is making your deadline.