Linux 4.14 Ensures The "Core Performance Boost" Bit Gets Set For AMD Ryzen CPUs

[soulsource]

/proc/cpuinfo does not display turbo frequencies. If you want to see those, you'll need another tool, like cpupower.

[Kendji]

There's virtually no or very little performance difference.

[dwagner]

Just start a single-threaded CPU eating process and watch the output of "turbostat" while it runs - I can see frequencies above the base clock being used, automatically, even though /proc/cpuinfo does not indicate "cpb".

[monte84]

I don't think CPB works with the performance CPU governor. When I enable the performance governor, all CPU cores at locked at their base frequency. I have watched through (watch grep "cpu MHz" /proc/cpuinfo)

[Zan Lynx]

I thought boost was used when the CPU was cool enough, how does this work for Ryzen when the thermal driver doesn't land until 4.15

The CPU knows its own internal temperature. AFAIK, XFR does not require anything from the OS. It just does its thing.

[FireBurn]

I thought boost was used when the CPU was cool enough, how does this work for Ryzen when the thermal driver doesn't land until 4.15

[tildearrow]

Minor typo?

and indicated from /proc/cpu via the flags line

(it's /proc/cpuinfo)

[phoronix]

Phoronix: Linux 4.14 Ensures The "Core Performance Boost" Bit Gets Set For AMD Ryzen CPUs

Recently making waves in our forums was talk of a kernel patch to address a case where the AMD CPB (Core Performance Boost) isn't being exposed by Ryzen processors. Here's more details on that and some benchmarks...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.14-AMD-CPB