On Fri, Aug 26, 2016 at 11:40:48AM -0700, Steve Muckle wrote: > A policy of going to fmax on any RT activity will be detrimental > for power on many platforms. Often RT accounts for only a small amount > of CPU activity so sending the CPU frequency to fmax is overkill. Worse > still, some platforms may not be able to even complete the CPU frequency > change before the RT activity has already completed. > > Cpufreq governors have not treated RT activity this way in the past so > it is not part of the expected semantics of the RT scheduling class. The > DL class offers guarantees about task completion and could be used for > this purpose.
Not entirely true. People have simply disabled cpufreq because of this. Yes, RR/FIFO are a pain, but they should still be deterministic, and variable cpufreq destroys that. I realize that the fmax thing is annoying, but I'm not seeing how rt_avg is much better.