Questions[turbo-boost](ubuntu)

This may be a terminology problem at my end and a duplicate: On Intel CPUs, I can relatively easy disable turbo boost at runtime by running something like

echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo

The CPU then runs at its base clock without "turboing up". The nice thing is that I do not need to change BIOS/(U)EFI settings for that.

What would be the equivalent (in terms of both terminology and commands) on AMD CPUs, specifically on a Zen-1 Epyc?

I am trying to run the CPU at constant (low) speed for consistent benchmark results. I am trying to compare different software implementations of algorithms.

I have a laptop with an Intel i7-1065G7 cpu. turbostat reports

35 * 100.0 = 3500.0 MHz max turbo 8 active cores
35 * 100.0 = 3500.0 MHz max turbo 7 active cores
35 * 100.0 = 3500.0 MHz max turbo 6 active cores
35 * 100.0 = 3500.0 MHz max turbo 5 active cores
35 * 100.0 = 3500.0 MHz max turbo 4 active cores
35 * 100.0 = 3500.0 MHz max turbo 3 active cores
38 * 100.0 = 3800.0 MHz max turbo 2 active cores
39 * 100.0 = 3900.0 MHz max turbo 1 active cores

(these are 4 physical/8 virtual cores) When I throw a large single-thread load (calculating pi with mpfr) at the cpu I observe that two cores (maybe one physical core?) run at exactly 3500 MHz while the others have a lower frequency. But they never reach the higher turbo boost frequencies.

If I disable some of the cpu cores (e.g. with echo 0 > /sys/devices/system/cpu/cpu[2-7]*/online) the laptop does reach the corresponding higher turbo boost frequencies, resulting in increased performance (a task that took on average 18.5 seconds before now takes 16.8).

How can I get my new laptop to reach its maximal clock speed when not all cores are needed?

I'm using Ubuntu 20.04 with kernel 5.4.0 on an HP Envy x360 laptop.

What I expect: On my old laptop with an i7-4712MQ turbostat gives

30 * 100.0 = 3000.0 MHz max turbo 4 active cores
30 * 100.0 = 3000.0 MHz max turbo 3 active cores
32 * 100.0 = 3200.0 MHz max turbo 2 active cores
33 * 100.0 = 3300.0 MHz max turbo 1 active cores

(this is also a 4/8 core machine). On this machine a single-core load makes one core boost to almost 3.3 GHz, under a two-core load two clock at 3.2 GHz etc.

I haven't checked individual cpu frequencies on Windows, but the task manager sometimes displays frequencies above 3.7GHz.

Update: So the problem disappeared... I have no idea why. I did uninstall linux-cloud-tools but I don't think this should be the reason.

I have Ubuntu 19.04 with all updates installed with Intel i9 9900k processor and Asrock H370M pro4 motherboard, it's updated to the latest bios.

I cannot make Turbo boost work for single thread loads (Which I have plenty of and boost in Ghz would be very helpful) If I run some inherently single thread load (and can confirm that only one core being loaded), for example:

sysbench --threads=1 --time=1000 --test=cpu run

I see all cores jump to 4.7Ghz. I expect the core that is under 100% load should jump to 5.0ghz

I have turbo boost enabled:

$ cat /sys/devices/system/cpu/intel_pstate/no_turbo
0

(if I disable it processor speed won't rise above 3.7)

I've read that sometimes some tools doesn't report accurate frequency and in fact turbo boost may work - I've tried multitude of tools with neither reported any different (all cores maxed at 4.7 doing single thread load).

turbostat for example correctly identifies turboboost parameters:

cpu1: MSR_IA32_POWER_CTL: 0x003c005d (C1E auto-promotion: DISabled)
cpu1: MSR_TURBO_RATIO_LIMIT: 0x2f2f2f3030313232
47 * 100.0 = 4700.0 MHz max turbo 8 active cores
47 * 100.0 = 4700.0 MHz max turbo 7 active cores
47 * 100.0 = 4700.0 MHz max turbo 6 active cores
48 * 100.0 = 4800.0 MHz max turbo 5 active cores
48 * 100.0 = 4800.0 MHz max turbo 4 active cores
49 * 100.0 = 4900.0 MHz max turbo 3 active cores
50 * 100.0 = 5000.0 MHz max turbo 2 active cores
50 * 100.0 = 5000.0 MHz max turbo 1 active cores

Still, under single thread load it also shows that all cores are at 4.7Ghz despite only single one is loaded:

$cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq
4815705
4721193
4799105
4772830
4794879
4782198
4891662
4714048
4749921
4737188
4801009
4859085
4734327
4735355
4747906
4826031

There is no setting in bios to make all cores always work at max speed (no core optimization or anything remotely related to cores), I've tried to played with all possible settings with no change.

I've tried to change cpu governor to performance with no effect - only all cores are constantly locked at 4.7 instead of on demand.

What's interesting, if I disable cores with echo 0 | sudo tee /sys/devices/system/cpu/cpu1/online and leave only 2 cores online - they do in fact reach 5.0 Ghz but that's definitely not a sustainable solution.

Please advise what can else be done

Thank you in advance!

I have an I7-8750H and currently have a dual boot machine with Win10 and Ubuntu 18.04 with the 4.18.8 kernel.

When I stress test all cores of the cpu in windows it reaches 3.9 GHz which is as it should, but when i stress test in Ubuntu, the cores only reach 2.5 GHz.

I have tried changing the scaling governor but doesn't change the outcome.

i7z says:

Socket [0] - [physical cores=6, logical cores=12, max online cores ever=6]
TURBO ENABLED on 6 Cores, Hyper Threading ON
Max Frequency without considering Turbo 2307.32 MHz (100.32 x [23])
Max TURBO Multiplier (if Enabled) with 1/2/3/4/5/6 Cores is  41x/41x/40x/40x/39x/39x

I have searched all the posts here on ask ubuntu on how to do this and can't seem to figure it out still. What is the best way to disable and enable turbo boost? My fans are running quite loud on my x220 so I'd like to disable it. Thanks!