RE: Skylake (XPS 13 9350) TSC is way off

["Brown, Len" <len.brown@intel.com>]

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> >> [    0.000000] tsc: PIT calibration matches HPET. 2 loops
> >> [    0.000000] tsc: Detected 2399.975 MHz processor
> >> [    0.090897] TSC deadline timer enabled
> >> [    1.960034] tsc: Refined TSC clocksource calibration: 2400.007 MHz

> turbostat version 4.10 10 Dec, 2015 - Len Brown <lenb@kernel.org>
> CPUID(0): GenuineIntel 22 CPUID levels; family:model:stepping 0x6:4e:3 (6:78:3)
> CPUID(1): SSE3 MONITOR EIST TM2 TSC MSR ACPI-TM TM
> CPUID(6): APERF, DTS, PTM, HWP, HWPnotify, HWPwindow, HWPepp, No-HWPpkg, EPB
> cpu1: MSR_IA32_MISC_ENABLE: 0x00850089 (TCC EIST MONITOR)
> CPUID(0x15): eax_crystal: 2 ebx_tsc: 200 ecx_crystal_hz: 0
> TSC: 2400 MHz (24000000 Hz * 200 / 2 / 1000000)
> CPUID(0x16): base_mhz: 2400 max_mhz: 2800 bus_mhz: 100


Both the initial and refined TSC calibration are right on the money -- 2400 MHz.
Further, this system happens to also have a base frequency of 2400 MHz,
so tsc_khz = cpu_khz = 2,400,000, exactly.  It would stray from that value
only based on the ppm error of the base 24 MHz crystal.

Anything other than that value is error.

-Len

> RAPL: 17476 sec. Joule Counter Range, at 15 Watts
> cpu1: MSR_PLATFORM_INFO: 0x4043df1011800
> 4 * 100 = 400 MHz max efficiency frequency
> 24 * 100 = 2400 MHz base frequency
> cpu1: MSR_IA32_POWER_CTL: 0x0024005d (C1E auto-promotion: DISabled)
> cpu1: MSR_TURBO_RATIO_LIMIT: 0x1b1b1b1c
> 27 * 100 = 2700 MHz max turbo 4 active cores
> 27 * 100 = 2700 MHz max turbo 3 active cores
> 27 * 100 = 2700 MHz max turbo 2 active cores
> 28 * 100 = 2800 MHz max turbo 1 active cores
> cpu1: MSR_CONFIG_TDP_NOMINAL: 0x00000017 (base_ratio=7)
> cpu1: MSR_CONFIG_TDP_LEVEL_1: 0x0008003c (PKG_MIN_PWR_LVL1=0
> PKG_MAX_PWR_LVL1=0 LVL1_RATIO=8 PKG_TDP_LVL1=60)
> cpu1: MSR_CONFIG_TDP_LEVEL_2: 0x001800c8 (PKG_MIN_PWR_LVL2=0
> PKG_MAX_PWR_LVL2=0 LVL2_RATIO=8 PKG_TDP_LVL2=200)
> cpu1: MSR_CONFIG_TDP_CONTROL: 0x00000000 ( lock=0)
> cpu1: MSR_TURBO_ACTIVATION_RATIO: 0x00000000 (MAX_NON_TURBO_RATIO=0
> lock=0)
> cpu1: MSR_NHM_SNB_PKG_CST_CFG_CTL: 0x1e008006 (UNdemote-C3,
> UNdemote-C1, demote-C3, demote-C1, locked: pkg-cstate-limit=6: pc8)
> cpu0: MSR_PM_ENABLE: 0x00000001 (HWP)
> cpu0: MSR_HWP_CAPABILITIES: 0x0105171c (high 0x1c guar 0x17 eff 0x5 low
> 0x1)
> cpu0: MSR_HWP_REQUEST: 0x80001c04 (min 0x4 max 0x1c des 0x0 epp 0x80
> window 0x0 pkg 0x0)
> cpu0: MSR_HWP_INTERRUPT: 0x00000001 (EN_Guaranteed_Perf_Change,
> Dis_Excursion_Min)
> cpu0: MSR_HWP_STATUS: 0x00000000 (No-Guaranteed_Perf_Change, No-
> Excursion_Min)
> cpu0: MSR_IA32_ENERGY_PERF_BIAS: 0x00000006 (balanced)
> cpu0: MSR_RAPL_POWER_UNIT: 0x000a0e03 (0.125000 Watts, 0.000061
> Joules, 0.000977 sec.)
> cpu0: MSR_PKG_POWER_INFO: 0x00000078 (15 W TDP, RAPL 0 - 0 W, 0.000000
> sec.)
> cpu0: MSR_PKG_POWER_LIMIT: 0x4280c800dd8078 (UNlocked)
> cpu0: PKG Limit #1: ENabled (15.000000 Watts, 28.000000 sec, clamp
> ENabled)
> cpu0: PKG Limit #2: ENabled (25.000000 Watts, 0.002441* sec, clamp
> DISabled)
> cpu0: MSR_DRAM_POWER_LIMIT: 0x5400de00000000 (UNlocked)
> cpu0: DRAM Limit: DISabled (0.000000 Watts, 0.000977 sec, clamp DISabled)
> cpu0: MSR_IA32_TEMPERATURE_TARGET: 0x00640000 (100 C)
> cpu0: MSR_IA32_PACKAGE_THERM_STATUS: 0x88340800 (48 C)
> cpu0: MSR_IA32_THERM_STATUS: 0x88350800 (47 C +/- 1)
> cpu1: MSR_IA32_THERM_STATUS: 0x88340800 (48 C +/- 1)
>     Core     CPU Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1
> CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Totl%C0  Any%C0  GFX%C0 CPUGFX%
> Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt
> RAMWatt   PKG_%   RAM_%
>        -       -      16    2.84     549    2399       0    4.13
> 0.02    0.63   92.39      46      46   12.21   10.77    2.48    0.80
> 14.33   71.53    0.00    0.00    0.00    0.00    0.00    1.95    0.54
>   0.00    0.00
>        0       0      11    1.92     563    2399       0    2.48
> 0.02    0.80   94.78      46      46   12.21   10.78    2.48    0.80
> 14.34   71.55    0.00    0.00    0.00    0.00    0.00    1.95    0.54
>   0.00    0.00
>        0       2       8    1.39     550    2399       0    3.04
>        1       1      13    2.04     622    2400       0    7.48
> 0.02    0.45   90.01      45
>        1       3      31    6.01     520    2400       0    3.51
> 1.002561 sec
> 
> In case it's at all useful, adjtimex -p says:
> 
>          mode: 0
>        offset: 0
>     frequency: 135641
>      maxerror: 37498
>      esterror: 1532
>        status: 8192
> time_constant: 2
>     precision: 1
>     tolerance: 32768000
>          tick: 10000
>      raw time:  1449098317s 671243180us = 1449098317.671243180
> 
> this suggests a rather small correction, so I really have no idea what
> "Adjusting tsc more than 11% (8039115 vs 7759462)" means.
> 
> John, you wrote this code.  What does the error message mean?
> 
> --Andy
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