Another look at HPET High Precision Event Timer

Discussion in 'Videocards - NVIDIA GeForce Drivers Section' started by Bukkake, Sep 18, 2012.

  1. alexander1986

    alexander1986 Master Guru

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    all good! suspected something like that, still wondering a little bit when and why windows uses HPET if ever (on intel cpu), and if you can completely disable any use of it via bios, I had the setting on my old system in bios to disable it there, but not on this new z390 chipset build, also imo its strange that setting the platformclock to HPET can drastically tank the fps in games like that on my system though,


    before I upgraded my whole build in May of this year I had a much older and slower system with an i5 and ddr3 ram + gtx 1060, setting the platformclock to HPET on that old system did also lower fps but did not make the system unusable and games unplayable like on my new , much faster system :S did make the mouse feel a lot more sluggish though but still, its strange, idk.
     
    Last edited: Nov 2, 2019
  2. alexander1986

    alexander1986 Master Guru

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    Aha, well, last question then if you know, would be what happens if you disable it via bios, provided you have the setting? I did have the bios setting on my old build but not on the current one, and on the old build when I set HPET as platformclock it did not decrease the performance so drastically as on my current build, still did decrease a bit but system was usable and games were playable still..
     
  3. janos666

    janos666 Master Guru

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    May be it's utilized when the TSC is unstable (if I recall correctly, when frequency scaling was a new thing, they initially forgot to keep the TSC [or it's equivalent back then] on a fixed clock, it went up and down with the CPU core clock, or something like that --- or they forgot to save and restore it's state after hibernation or deep C states [power-save feature which cuts clocks and optionally voltages from parts of the CPU], or something like that). But that's really old stuff, like Pentium 4 era old. I am not sure if Win10 runs on those CPUs anymore. Although this setting was inherited from Win8 or earlier (may be as early as Vista).
    HPET itself, I think, was introduced before TSC (or before TSC was fast and stable enough) and was meant for multi-media. But that was also 10+ years ago. I think Microsoft redesigned Windows 10's timing system just a few semi-annual build ago.
     
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  4. Astyanax

    Astyanax Ancient Guru

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    its not that its forgotten, the ryzen cpu has no way to restore that state of the chip and will always come out of sleep with timer issues.
     

  5. mbk1969

    mbk1969 Ancient Guru

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    What state?
    What sleep?
    What timer issues?
     
  6. Astyanax

    Astyanax Ancient Guru

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    Ryzen processors do not restore coherency when a core resumes from low power or after a S3 sleep cycle, this was the cause of the Destiny 2 start issue with Ryzen 3k and also the reason that they have that inflated benchmark results issue after a resuming from S3.

    things like this happen where the timers are off
    https://forums.elderscrollsonline.c...ryzen-sleep-bug-acts-like-a-speed-hack-in-eso

    when hpet is available the system timers get recalibrated against the hpet clock occasionally
     
  7. mbk1969

    mbk1969 Ancient Guru

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    Why do you think HPET is used for that?
     
  8. Astyanax

    Astyanax Ancient Guru

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  9. mbk1969

    mbk1969 Ancient Guru

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  10. dexterav

    dexterav Member Guru

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    i just try enabling HPET on my dell g5 5590 just for curiosity and results its horrible :D
    i almost dont be capable return HPET to OFF state because was unbelievable slow
     

  11. mbk1969

    mbk1969 Ancient Guru

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    Enabled how exactly?
     
  12. dexterav

    dexterav Member Guru

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    no bios options , from win
    i have similar experience with my z370f, hpet on, and system is very very slow
     
  13. mbk1969

    mbk1969 Ancient Guru

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    If you mean "set useplatformclock yes" then this is forcing, not enabling. And on systems without HPET (or with HPET disabled in BIOS) that mode will force to use other platform timers.
    Forcing to use any platform timer (as implementation of two specific API functions) is bad only because the time penalties for using timers outside of CPU are huge.
     
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  14. Hemisfear

    Hemisfear Active Member

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    funny how this is still a thing in 2019
     
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  15. mbk1969

    mbk1969 Ancient Guru

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    Yeah. I have to work better to restrain myself from posting in this thread. So far I failed.
     
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  16. TheDukeSD

    TheDukeSD Member Guru

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    Some (if not all) AMD AM2 cpu don't have invariant TSC. I know for sure Brisbane cpus (cause I have 2 :p) don't have invariant TSC as result TSC is mark as unstable and not used.
    You can run Win 10 on Brisbane cpus because they have all the needed instructions (at least up to september 2019 it was possible to run win 10, that's the time I tried to run Win 10 on a Brisbane cpu, with Win 10 being a rolling release it's possible that one release to require something not supported by Brisbane cpus).

    "set useplatformclock no" (HPET enabled in bios) - on my G3260 makes at least one game feel smoother when fps is spiking.
    Both Brisbane cpu I have feel smoother in games with HPET disabled in bios, but this might be due to buggy HPET implementation in the AM2 motherboards I have (Linux complains about HPET in one case).
    Keep in mind that I said feels, and well how something feels depends from person to person.

    If I remember right disabling HPET in bios made one benchmark refuse to work, forgot the name of the benchmark.
     
    Last edited: Nov 4, 2019
  17. dexterav

    dexterav Member Guru

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    on z370f just slowing NVME ssd to half speed and horrible acess time
    i just try using hpet on only for benchmarking , need HPET on its specific bench rest of pc working ok
    on dell going to crap whole system
    problem of HPET is behavior like crap and with random resultson same PC
    i supose best thing is forget HPET exist and we will be happy :D
     
  18. X7007

    X7007 Ancient Guru

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    What fixed my Mouse issues are as follows from top to low. this will depend on your spec I think Intel and AMD, some things won't effect like mine.

    Disable Spectre protection using InSpectre.exe

    Command Prompt
    bcdedit /set DisabledynamicTick Yes
    bcdedit /set useplatformTick Yes

    Put GPU on MSI mode using MSI_util_v2.exe

    Change Drivers files Core Affinity offloading from Core0... Only GPU/USB using interrupt_affinity_policy_tool.msi

    DO NOT Install Windows Sandbox


    Obviously things to do

    Power Mangement High Performance or Ultra


    Bios

    CPU Phase Power Mode Should be High Performance or Extreme
    DRAM also Extreme
    Legacy USB Doesn't seem to have big effect / Still checking
    Secure Boot does not have any effect, also it doesn't really enabled, if you do not enable the GPEDIT.msc
    https://www.tenforums.com/tutorials/...dows-10-a.html
    HPET Enabled in Bios
     
  19. Astyanax

    Astyanax Ancient Guru

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    You're not fixing issues with this, you're adding them.

    mouse lag will scale with cpu load here.
     
  20. mbk1969

    mbk1969 Ancient Guru

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    Why? Share your knowledge.
     

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