> >But what sense does it make for a user,sysadmin or > >application > >to change voltage? If any of these want to save power, > >they do so > >by a) doing less work, and then b) lowering the clock > >speed as this > >is inherently tied to voltage. > > It makes sense to perform changing an operating point > dynamically in > userland. In very special cases, yes. > That said, voltage should be accessible from userland. Why? If few states differ in voltage but not frequency, the only user-visible thing is different latency of enter/exit. If you only have two voltages per frequency (as it was shown in examples here)... just add 1Hz to make difference between the two. ...but I guess you should teach cpufreq's ondemand governor to deal with different latencies for different voltages. Before that is done and shown to have significant power-saving impact, userspace interface debate is useless. Pavel -- Thanks for all the (sleeping) penguins.
