Weird processor frequency issues

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From: Kevin Oberman <rkoberman_at_gmail.com>
Date: Wed, 13 Oct 2021 23:44:51 UTC
I am seeing very strange CPU frequency issues on my Lenovo L15 with a
CPU: Intel(R) Core(TM) i5-10210U CPU @ 1.60GHz (2112.13-MHz K8-class CPU)
  Origin="GenuineIntel"  Id=0x806ec  Family=0x6  Model=0x8e  Stepping=12

eatures=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>

eatures2=0x7ffafbbf<SSE3,PCLMULQDQ,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,SDBG,FMA,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND>
  AMD Features=0x2c100800<SYSCALL,NX,Page1GB,RDTSCP,LM>
  AMD Features2=0x121<LAHF,ABM,Prefetch>
  Structured Extended
eatures=0x29c67af<SGSBASE,TSCADJ,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,NFPUSG,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PROCTRACE>
+  Structured Extended
Features3=0xbc000400<MD_CLEAR,IBPB,STIBP,L1DFL,ARCH_CAP,SSBD>
  XSAVE Features=0xf<XSAVEOPT,XSAVEC,XINUSE,XSAVES>
  IA32_ARCH_CAPS=0x2b<RDCL_NO,IBRS_ALL,SKIP_L1DFL_VME,MDS_NO>
  VT-x: PAT,HLT,MTF,PAUSE,EPT,UG,VPID
  TSC: P-state invariant, performance statistics

The system is running with P-States disabled as this s one of the Lenovo
mobile systems that locks up when they are enabled.


The reported frequency of all threads is constant.
> sysctl dev.cpu | grep freq:
dev.cpu.7.freq: 400
dev.cpu.6.freq: 400
dev.cpu.5.freq: 400
dev.cpu.4.freq: 400
dev.cpu.3.freq: 400
dev.cpu.2.freq: 400
dev.cpu.1.freq: 400
dev.cpu.0.freq: 2101

If I do something that runs all 8 threads at near 100% for any length of
time, the core temps will increase to over 90C. I will log:
coretemp0: critical temperature detected, suggest system shutdown
After that is received, the system starts to cool, eventually reaching the
low 40s. All CPUs continue to show near 100% utilization. It will then
repeat the cycle. All continue to show frequencies as above, CPU 0 at 2101
and the remainder at 400.

I have never seen such behavior and am baffled by it. That issue was
reported in 248659
<https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=248659> and 253288
<https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253288> with P-States
seems likely to be related. (BTW, these tickets should be merged as they
are reporting the same problem.)

Would a bug report be appropriate? The P-State issue was reported over a
year ago and is still in the "New" state. It has been widely reported, most
recently a few hours ago.
--

Kevin Oberman, Part time kid herder and retired Network Engineer
E-mail: rkoberman@gmail.com
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683