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konkor / cpufreq

System Monitor and Power Manager
https://konkor.github.io/cpufreq/
GNU General Public License v3.0
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Unclear intel pstate behavior #39

Open konkor opened 7 years ago

konkor commented 7 years ago

Here is an example. Some Intel CPU has frequencies 1200-2600 MHz (3200 with turbo boost). So minimum frequency is 1200/3200 = 38%, max is 2600/3200 = 81%, max with TB is 3200/3200 = 100%. But here is other problems too. The newest kernels 4x is supporting it by own way. It's looking like Intel doesn't have standard yet, one kernels allow you to set frequency from 0% to 100% other not. Here is same problem with governors so. So in some cases Turbo Boost behavior is not clear too. At the end latest kernels are supporting ACPI CPUFREQ too through ACPI profiles but limited it's frequencies only. So if Intel driver is looking back anyway to ACPI DRIVER now is it any profit from using it? Maybe it's time to change to local units from 1.2GHz to 3.2GHz to example so? But it's a lot of work because of its behavior... Any suggests will be good point to decide of future of intel pstate mode in the application.

RicardoEPRodrigues commented 7 years ago

Is it possible to contact the developers at intel? (may be a long shot but if they reply it's worth it)

Or contact the kernel developers to see if they know the course of action.

I think for now the percentage being at 38% and 81% isn't really breaking the experience. Sooner or later people realize that the 38% is the minimum (in my case was 22%).

konkor commented 7 years ago

@RicardoEPRodrigues it's good idea but i can't do it without wide statistic. I don't have any available hardware to test it so. I have one broken laptop and 2 other machines without supporting of the intel pstate and I don't have an opportunity to buy/upgrade new hardware to test it. It's very complicated. Sadly I have other priorities now. Heh

RicardoEPRodrigues commented 7 years ago

Is this bug breaking anything? If not then let's wait until the end of the year and after 8th gen comes out, maybe then I'll buy a Intel laptop and we could give it a try.

Or maybe by that time you'll have the opportunity to buy hardware.

Additionally contacting Intel and telling them about this and even requesting hardware maybe help. No is what you'll expect, but they may surprise you.

konkor commented 7 years ago

@RicardoEPRodrigues can you test info branch on intel_pstate? I have changed setting frequency algorithm to avoid some breaking issues when new min > current max or max < min...

I have noticed it at intel_pstate mode last time I tested 4.12. When you set min/max to 50/50% and then moving min slider to 60/60% it can't apply min freq because new min freq is still less then current max and frequencies are getting 50/60%... and conversely. So it can be related to #37 too. Thank you.

RicardoEPRodrigues commented 7 years ago

Unfortunately I no longer have an Intel device (AMD Ryzen is the best :smile: ), but I think later in the year I might buy one Intel laptop.

ayoungethan commented 5 years ago

I have an 8th gen intel CPU, is there something I can do to clarify this issue?

When I set sliders both to 0% my cpu frequency stays at 400mhz

konkor commented 5 years ago

@ayoungethan 1) you can disable intel-pstate driver 2) It's your minimal base frequency and can't go lower.