Comment 1 for bug 862785

I can comment on this. First off, sampling_down_factor = 1 disables the feature, so it is a bit the opposite of what you describe. I believe what's happening is that ondemand can fail for certain cpu's (including mine), and instead of amping up the frequency under heavy load, it will resonate the frequency, switching it up and down.

sampling_down_factor delays, geometrically, how fast ondemand will down scale the frequency, and can thus reduce this issue.

From the patch author: "Set to 1 it makes no changes from existing behavior, but set to greater than 1 (e.g. 100) it acts as a multiplier for the scheduling interval for reevaluating load when the CPU is at its top speed due to high load. This improves
performance by reducing the overhead of load evaluation and helping the CPU stay at its top speed when truly busy, rather than shifting back and forth in speed. This tunable has no effect on behavior at lower speeds/lower CPU loads."

It's been awhile since I've looked at this, but running a few javascript tests, it looks like I still have this issue. I guess I need to work this tunable myself!