[Bug 215729] New: amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

[Bug 215729] New: amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=215729

            Bug ID: 215729
           Summary: amd-pstate driver has a much higher idle power
                    consumption for a desktop Zen 3 CPU
           Product: Power Management
           Version: 2.5
    Kernel Version: 5.17
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: cpufreq
          Assignee: linux-pm@vger.kernel.org
          Reporter: aros@gmx.com
        Regression: No

I have a Ryzen 7 5800X CPU.

With the acpi-cpufreq driver the CPU idles around 20W, frequencies are in the
range of 2.2-2.8GHz.

The very same system with the amd-pstate driver idles around 25W frequencies
are in the range of 3.9-4.75GHz.

This doesn't look right.

Changing governor from ondemand to powersave reduces idle power consumption to
around 21.5W (still higher than with acpi-cpufreq) but this obvious completely
destroys performance.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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--- Comment #1 from Artem S. Tashkinov (aros@gmx.com) ---
At least under Windows 10 I see effective frequencies around 50MHz (i.e. cores
are idling as much as possible), that doesn't seem to be the case with Linux.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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https://bugzilla.kernel.org/show_bug.cgi?id=215729

Artem S. Tashkinov (aros@gmx.com) changed:

           What    |Removed                     |Added
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                 CC|                            |ray.huang@amd.com

--- Comment #2 from Artem S. Tashkinov (aros@gmx.com) ---
CC'ing Huang Rui - please check.

I'm not changing any CPU frequency related options - i.e. everything is running
by default.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=215729

Huang Rui (huangrui@mail.ustc.edu.cn) changed:

           What    |Removed                     |Added
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                 CC|                            |huangrui@mail.ustc.edu.cn

--- Comment #3 from Huang Rui (huangrui@mail.ustc.edu.cn) ---
(In reply to Artem S. Tashkinov from comment #0)
> I have a Ryzen 7 5800X CPU.
> 
> With the acpi-cpufreq driver the CPU idles around 20W, frequencies are in
> the range of 2.2-2.8GHz.
> 
> The very same system with the amd-pstate driver idles around 25W frequencies
> are in the range of 3.9-4.75GHz.
> 
> This doesn't look right.
> 
> Changing governor from ondemand to powersave reduces idle power consumption
> to around 21.5W (still higher than with acpi-cpufreq) but this obvious
> completely destroys performance.

Thanks to report the issue. Could you please dump the print of "lscpu" and use
the latest bleeding-edge source code include the CPUPower support
(https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/log/?h=bleeding-edge)
to print "cpupower frequency-info"?

Thanks,
Ray

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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https://bugzilla.kernel.org/show_bug.cgi?id=215729

--- Comment #4 from Artem S. Tashkinov (aros@gmx.com) ---
With acpi-cpufreq:

# lscpu

Architecture:            x86_64
  CPU op-mode(s):        32-bit, 64-bit
  Address sizes:         48 bits physical, 48 bits virtual
  Byte Order:            Little Endian
CPU(s):                  16
  On-line CPU(s) list:   0-15
Vendor ID:               AuthenticAMD
  BIOS Vendor ID:        Advanced Micro Devices, Inc.
  Model name:            AMD Ryzen 7 5800X 8-Core Processor
    BIOS Model name:     AMD Ryzen 7 5800X 8-Core Processor             
    CPU family:          25
    Model:               33
    Thread(s) per core:  2
    Core(s) per socket:  8
    Socket(s):           1
    Stepping:            0
    Frequency boost:     enabled
    CPU max MHz:         4928.1250
    CPU min MHz:         2200.0000
    BogoMIPS:            7600.48
    Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt
pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid
aperfmperf rapl pni pclmul
                         qdq monitor ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt
aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a
misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core
perfctr_nb bpext perfctr_l
                         lc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs
ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed
adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc
cqm_occup_llc cqm_mbm_total 
                         cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd
arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists
pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku vaes
vpclmulqdq rdpid ov
                         erflow_recov succor smca fsrm
Virtualization features: 
  Virtualization:        AMD-V
Caches (sum of all):     
  L1d:                   256 KiB (8 instances)
  L1i:                   256 KiB (8 instances)
  L2:                    4 MiB (8 instances)
  L3:                    32 MiB (1 instance)
Vulnerabilities:         
  Itlb multihit:         Not affected
  L1tf:                  Not affected
  Mds:                   Not affected
  Meltdown:              Not affected
  Spec store bypass:     Mitigation; Speculative Store Bypass disabled via
prctl
  Spectre v1:            Mitigation; usercopy/swapgs barriers and __user
pointer sanitization
  Spectre v2:            Mitigation; Retpolines, IBPB conditional, IBRS_FW,
STIBP always-on, RSB filling
  Srbds:                 Not affected
  Tsx async abort:       Not affected

# ./cpupower frequency-info
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 2.20 GHz - 4.93 GHz
  available frequency steps:  3.80 GHz, 2.80 GHz, 2.20 GHz
  available cpufreq governors: conservative ondemand userspace powersave
performance schedutil
  current policy: frequency should be within 2.20 GHz and 3.80 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency: 2.20 GHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes
    Boost States: 0
    Total States: 3
    Pstate-P0:  3800MHz
    Pstate-P1:  2800MHz
    Pstate-P2:  2200MHz

Will post the results of `cpupower frequency-info` under amd-pstate a tad
later.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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--- Comment #5 from Artem S. Tashkinov (aros@gmx.com) ---
Under amd-pstate:

# lscpu

    Frequency boost:     enabled
    CPU max MHz:         4929.0000
    CPU min MHz:         550.0000
    BogoMIPS:            7599.66

(everything else is obviously the same)

# ./cpupower frequency-info
analyzing CPU 0:
  driver: amd-pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 131 us
  hardware limits: 550 MHz - 4.93 GHz
  available cpufreq governors: conservative ondemand userspace powersave
performance schedutil
  current policy: frequency should be within 550 MHz and 4.93 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 903 MHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes
    AMD PSTATE Highest Performance: 166. Maximum Frequency: 4.93 GHz.
    AMD PSTATE Nominal Performance: 128. Nominal Frequency: 3.80 GHz.
    AMD PSTATE Lowest Non-linear Performance: 59. Lowest Non-linear Frequency:
1.75 GHz.
    AMD PSTATE Lowest Performance: 19. Lowest Frequency: 550 MHz.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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--- Comment #6 from Artem S. Tashkinov (aros@gmx.com) ---
After rebooting again with amd-pstate the situation has kinda improved:

Max CPU frequency in idle is now around 1.2GHz with occasional spikes to
2.2GHz.

Power consumption is now around 23W - not a big difference with acpi-cpufreq
but I was under the impression that amd-pstate should be more power efficient,
not less.

'Minimum' governor is now at around ~20W in idle which matches acpi-cpufreq.

----

Here's the most important thing:

The ondemand governor in idle makes the CPU consume around 23.5W

The performance governor in idle makes the CPU consume around 20.5W which is
near perfect.

So, it looks like the ondemand governor falters with amd-pstate for some
reasons. Maybe it does more work than necessary, maybe it gets called far too
often, I've no idea.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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--- Comment #7 from Artem S. Tashkinov (aros@gmx.com) ---
The conservative governor idles around 21W which is good but this governor is
very undesirable for a desktop system: it's too slow to react to instantaneous
spikes in workload and it makes e.g. web browsing far from comfortable.

So, with amd-pstate in idle:

Powersave and performance (!) governors ~ 20W.
Conservative ~ 21W.
Ondemand ~ 23.5W.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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Joe (sujinzhou2008@126.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sujinzhou2008@126.com

--- Comment #8 from Joe (sujinzhou2008@126.com) ---
Hello,

I reproduce this issue on my local.  

Your device (CPU family:  25, Model:  33) should be shared memory solution with
AMD P-state driver. Updating CPPC request with shared memory will need more
energy  than writing MSR register directly. We are checking this issue now.

For ondemand governor, could you please try to reduce the sampling_rate and
then check to energy consumption again? Thanks a lot!

Here is the command 

cd /sys/devices/system/cpu/cpufreq/ondemand
echo 50000 > sampling_rate

Thanks
Joe

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--- Comment #9 from Artem S. Tashkinov (aros@gmx.com) ---
(In reply to Joe from comment #8)
> Hello,
> 
> I reproduce this issue on my local.  
> 
> Your device (CPU family:  25, Model:  33) should be shared memory solution
> with AMD P-state driver. Updating CPPC request with shared memory will need
> more energy  than writing MSR register directly. We are checking this issue
> now.
> 
> For ondemand governor, could you please try to reduce the sampling_rate and
> then check to energy consumption again? Thanks a lot!
> 
> Here is the command 
> 
> cd /sys/devices/system/cpu/cpufreq/ondemand
> echo 50000 > sampling_rate
> 
> Thanks
> Joe

Changing sampling_rate from default 2000 to 50000 has improved the situation
considerably but still acpi-cpufreq has a tiny better idle power consumption.

acpi-cpufreq: ~20W
amd-pstate with default ondemand settings: ~23W
amd-pstate with ondemand/sampling_rate=50k: ~21W

Looks like the ondemand scheduler is not super efficient with the amd-pstate
driver.

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[Bug 215729] amd-pstate driver has a much higher idle power consumption for a desktop Zen 3 CPU

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--- Comment #10 from Artem S. Tashkinov (aros@gmx.com) ---
Kernel 6.3.12, default settings:

acpi-cpufreq: ~19.4W
amd-pstate: ~20.7W

Much better but not perfect. I can live with that but I still expected the
amd-pstate driver to be more effective considering its using native interfaces.



Not using any boot flags except: amd_pstate=active

/sys/devices/system/cpu/cpufreq/policy0 $ grep -r . 
energy_performance_available_preferences:default performance
balance_performance balance_power power 
amd_pstate_highest_perf:166
scaling_min_freq:550000
scaling_available_governors:performance powersave
scaling_governor:powersave
cpuinfo_max_freq:4929000
amd_pstate_lowest_nonlinear_freq:1752000
amd_pstate_max_freq:4929000
related_cpus:0
scaling_cur_freq:550000
scaling_setspeed:<unsupported>
affected_cpus:0
scaling_max_freq:4929000
cpuinfo_transition_latency:0
energy_performance_preference:performance
scaling_driver:amd-pstate-epp
cpuinfo_min_freq:550000

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Artem S. Tashkinov (aros@gmx.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |OBSOLETE

--- Comment #11 from Artem S. Tashkinov (aros@gmx.com) ---
~1W is nothing to worry about, let's close this bug report.

For mobile CPUs there's seemingly no difference at all.

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