Linux 4.17 Offers Some Promising Power-Savings Improvements

Then I decided to move to the other end of the spectrum... A dual-socket Intel Tyan Xeon Scalable server platform with two Xeon Gold 6138 processors. This system happened to be running Debian testing while again testing Linux 4.15 and 4.16 stable and then Linux 4.17 Git as of today.

On this Tyan server, the idle power usage ended up being the same across these three most recent kernel branches. However, the power usage under load was found to have some nice improvements.

The PostgreSQL performance was within its margin of error between the three tested kernels...

But the power usage was found to be noticeably better with Linux 4.17... An average savings of about 20 Watts while the peak power use was also down 9~18 Watts.

So on a performance-per-Watt basis, it's a fairly significant jump with Linux 4.17

For a variety of other Linux benchmarks, it ended up being a similar situation of seeing slightly lower power use under load while delivering roughly the same performance as the previous kernels.

Here's a look at the AC system power consumption for this dual Xeon Gold server over the course of many benchmarks. The average power use when running on Linux 4.17 was on average around thirty Watts lower than with Linux 4.15 or 4.16. The peak power use was also about 30 Watts less on Linux 4.17 while running all of the same workloads in a fully-standardized and automated manner using the Phoronix Test Suite.

I did run some quick tests on AMD Ryzen too, but at least there the results were indifferent. Anyhow, I have more tests planned over the days ahead and so stay tuned. I'm optimistic that these Linux 4.17 improvements may help close the gap I've been seeing for years where Windows -- especially on laptops -- has remained much more power efficient than Linux systems. I'll be doing some Windows vs. Linux (and potentially macOS) power comparisons on each platform's latest software as soon as time allows. If you enjoy all of the testing I do on Phoronix every single day, please consider showing your support by going premium or tips are welcome as well.

See our Linux 4.17 feature overview to learn about all of the other great features coming with this kernel that should be introduced as stable in June.