Meteor Lake EPP Tuning For Greater Performance Or Power Efficiency With Intel Ultra Core 7

[Mitch]

Race-to-idle is too simple of a paradigm on its own. It generally doesn't work well if your power curve gets too tapered off. If we require 300 percent of the power at one clockspeed to finish the work 4% sooner vs a lower clockspeed, then race-to-idle does not apply and we have wasted energy. Race-to-idle may apply up to certain clockspeeds, but it simply cannot apply to all available clockspeeds, especially the highest ones (usually in the upper limits of turbo speeds).

[coder]

It would be neat if you could disable the P cores through power-profiles-daemon in a battery save mode, and if there was an extreme battery save mode that powers down everything except the LP E cores (e.g. I'm on a long flight to India and I'm just catching up on email and watching movies and a dual core 2.5 GHz peak is fast enough).

Intel published some data specifically on power usage during video playback that's remarkably low. They're presumably only using the SoC tile, in that case. It's probably what motivated them to separate the media engine, display engine, & display PHYs from the GPU tile, which should then be able to sleep.

Putting the LP E-cores in the SoC tile was clearly done so they could power down the entire CPU tile.

[coder]

Michael how do you calculate performance/watt?

I think it's just simple perf/W_avg.

If you want cumulative energy usage, read the fine print at the bottom of the CPU Power Consumption graphs. There, you'll see it lists the total Joules consumed in each run.