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Journeyman III
Journeyman III

ADL Overdrive8 Frequency/Voltage

Hello, everyone!

I am new here, but probably I have a real question that I did not find answer for on this forums using search.

I am writing a C++ application using ADL SDK 13 that is capable of tweaking GPU Frequency and Voltage, similar to 2020 Radeon Software tuning feature. I wrote code based on display-library/Overdrive8.cpp at master · GPUOpen-LibrariesAndSDKs/display-library · GitHub  example and it works, I am able to set individual values for any of freq or voltage settings. What I am missing is auto-adjustment, like if you change Frequency slider in Radeon Software, and Voltage automatically tunes. I tried percentage scaling, but immediately run into limits for Freq and Voltage not matching, e.g. minimal voltage setting did not mean minimal frequency because GPU could perform with better-than-minimal freq at minimal voltage. Same situation with upper limit - max frequency could be saturated with less than maximum voltage. On the attached image you can see that in my case max possible freq is achieved on just 60% of voltage. And on other GPUs, I imagine, those proportions are different each time.

This leads to my question, how can I learn or calculate those proportions to do similar auto-adjust for any given GPU?

I have just noticed that there is 14 version of ADL released, but from brief looking at the changes I did not see anything related that could help me. I will update ASAP anyway.

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Staff
Staff

Re: ADL Overdrive8 Frequency/Voltage

Thank you for the above query. I'll check with the ADL team for their suggestion regarding this.

Also, I have whitelisted you for the DevGurus community.

Thanks.

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Staff
Staff

Re: ADL Overdrive8 Frequency/Voltage

As the concerned team has replied, below is how the GFX curve works:

The driver sends three default points, and the UI calculate the parabola coefficient based on these three points. The UI saves the coefficient, and when the user changes Fmax / Fmin sliders, the UI calculates the corresponding voltage for these three points. Dragging these three points vertically(changing their voltage only) will change the saved coefficient.

A user can get these three points from ADL using ADL2_Overdrive8_Current_SettingX3_Get.

In the returned structure: int** lppCurrentSettingList , please check for these entries in the array:

OD8_SETTING_GFXCLK_FMAX = 0,
OD8_SETTING_GFXCLK_FMIN = 1,
OD8_SETTING_GFXCLK_FREQ1 = 2,
OD8_SETTING_GFXCLK_VOLTAGE1 = 3,
OD8_SETTING_GFXCLK_FREQ2 = 4,
OD8_SETTING_GFXCLK_VOLTAGE2 = 5,
OD8_SETTING_GFXCLK_FREQ3 = 6,
OD8_SETTING_GFXCLK_VOLTAGE3 = 7,

They represent the Fmax / Fmin and all the three points. Fmax = FREQ3, Fmin = FREQ1 and FREQ2 = (FREQ3 + FREQ1) / 2

In RSX, we check approx. every 3 secs, if points get changed(usually is the case that we applied our settings), we update the coefficient.

Thanks.

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Journeyman III
Journeyman III

Re: ADL Overdrive8 Frequency/Voltage

Thank you, I will definitely try this!

Since then I started gathering a table of values for GPUs I care about at first to see if any pattern is present. If parabola coefficient suits for any given card, this is definitely easier

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