AMD Brings Ryzen Overclocking Driver to Linux

AMD has published Linux kernel patches for an official Ryzen overclocking driver that allows users to adjust CPU power and current limits through a firmware interface exposed via sysfs. Phoronix reports: AMD engineer Shyam Sundar S K posted the patches for the AMD Overclocking "AOD" WMI driver as an interface to the platform firmware for managing overclocking and power/current limits of modern Ryzen CPUs.

The driver in its initial form allows setting via sysfs a number of CPU tunables including the Package Power Tracking (PPT), Thermal Design Current (TDC), and Electrical Design Current (EDC) limits along with reading their supported range. SMT toggling can also be done via the interface as an alternative to the likes of Linux's "nosmt" option in disabling SMT at the platform level rather than kernel disabling. The current memory clocks can also be read via this AOD driver.

The power tunables aren't applied in real-time but go into effect at next reboot. The firmware does support many more commands compared to the few initially wired up and hopefully in time more of these controls will be enabled with this driver.

Just in time

[PPH]

Winter is coming. And I need to get the office space heater fired up.

Re:

[doesnothingwell]

I just disabled PBO on two motherboards because I didn't want a space heater or damage another cpu. One older cpu went flakey with "cpu errors" after two years and would only run at reduced load.

In the olden days you never ran hardware above 80 c. A linux utility for monitoring power is ok, but I'm done frying silicon for a few more mips.

Re:

[Fly Swatter]

In the olden days if you forgot to put the heat sink on, an AMD would let the smoke out almost instantly when fired up.

- fired, see what I did there?

Re:

[T34L]

The new OS control still improves that game too, though; giving you for instance the option to heavily current limit the CPU when the machine is under low load that doesn't care about minimizing latency, which will increase thermal stability (and to a point, energy efficiency and overall thermal stress).

Re:

[thegarbz]

In the olden days you never ran hardware above 80 c.

In the olden days the chip in your CPU was made from different materials assembled in a different way than today. Not all silicon is the same, not all transistors are the same. There's a reason why some devices burn out at 75C junction temperature, and others can stand easily over 150C.

Also we don't measure temperature the same as we always did. That 80C in your "olden days" CPU... it probably is the same 100C as your current one. Multi-point precision on die temperature sensing is something from the past d

Re:

[bill_mcgonigle]

> One older cpu went flakey with "cpu errors"

That's often the thermal paste drying out. Clean the fan, repaste the chip, good for a few more years.

Usually.

Re:

[Mr. Dollar Ton]

It's called compewt now, not waste heat.

Seasonal GPU mining

[drnb]

Winter is coming. And I need to get the office space heater fired up.

A space heater? Did you perhaps mean the seasonal GPU mining? :-)

Re:

[bn-7bc]

A gpu miner is a vety inefficient heater to much energu goes into mining coins, traditional resistive heating is 100% efficient when it comes to converting electricity to heat, your GPU can't even get close

Re:

[fr]

Erm, so what other than heat is this electrical energy transformed into?
Back to Physics 101.

Re:

[higuita]

Go check https://www.youtube.com/watch?... [youtube.com]

Re:

[drnb]

But its a heater that pays for itself to some degree. :-)

How about underclocking?

[Torp]

I'd like to be able to fine tune the CPU towards using *less* power not more. I have a separate heating system thank you very much.

Re:

[DrMrLordX]

Most Windows "overclockers" are using PBO with the curve optimizer on any recent AMD CPU to actually run undervolted.

Re:

[fred6666]

it's called CPU frequency scaling and has been supported since about 20 years now

Re:

[nightflameauto]

I'd like to be able to fine tune the CPU towards using *less* power not more. I have a separate heating system thank you very much.

As a guy who spends a lot of time just writing, it'd be great if there was an automated "set to normal" that kicks in when I send a task to one of the taxing queues for the processor, and keeps it hovering just above "noticeable lag in the editor" the rest of the time. Underclocking would be great as my daily driving range, with automated 'turn it up' when I kick on the local AI driven editing routines that spill out of the GPU at times.

Re: How about underclocking?

[drinkypoo]

There are CPU governors which can help with that. It's gotten easier to play with them recently

Re:

[short]

for i in /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq;do cat `echo $i|sed 's/max/min/'` >$i;done