Messages in this thread | | | Date | Tue, 23 May 2023 22:31:07 +0800 | From | Feng Tang <> | Subject | Re: [PATCH RFC] x86/tsc: Make recalibration default on for TSC_KNOWN_FREQ cases |
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On Tue, May 23, 2023 at 10:11:15AM +0200, Peter Zijlstra wrote: > On Tue, May 23, 2023 at 09:18:23AM +0800, Feng Tang wrote: > > On Mon, May 22, 2023 at 06:11:58PM +0200, Peter Zijlstra wrote: > > > On Mon, May 22, 2023 at 11:20:15PM +0800, Feng Tang wrote: > > > > > > > And I don't understand the commit log: "On Intel GOLDMONT Atom SoC > > > > TSC is the only reliable clocksource. We mark TSC reliable to avoid > > > > watchdog on it." > > > > > > > > Clearly the Denventon I found today has both HPET and ACPI_PM timer: > > > > > > > > [root@dnv0 ~]# grep . /sys/devices/system/clocksource/clocksource0/* > > > > /sys/devices/system/clocksource/clocksource0/available_clocksource:tsc hpet acpi_pm > > > > /sys/devices/system/clocksource/clocksource0/current_clocksource:tsc > > > > > > > > The lscpu info is: > > > > > > > > Architecture: x86_64 > > > > CPU op-mode(s): 32-bit, 64-bit > > > > Address sizes: 39 bits physical, 48 bits virtual > > > > Byte Order: Little Endian > > > > CPU(s): 12 > > > > On-line CPU(s) list: 0-11 > > > > Vendor ID: GenuineIntel > > > > BIOS Vendor ID: Intel(R) Corporation > > > > Model name: Intel(R) Atom(TM) CPU C3850 @ 2.10GHz > > > > BIOS Model name: Intel(R) Atom(TM) CPU C3850 @ 2.10GHz CPU @ 2.1GHz > > > > BIOS CPU family: 43 > > > > CPU family: 6 > > > > Model: 95 > > > > Thread(s) per core: 1 > > > > Core(s) per socket: 12 > > > > Socket(s): 1 > > > > Stepping: 1 > > > > > > > > Maybe this cpu model (0x5F) has been used by some type of platforms > > > > which has met the false alarm watchdog issue. > > > > > > It has them; but they are not *reliable*. > > > > Yes, that's possible. I tried to CC the author Bin in case he can > > provide more background or information for his statement, but his > > email address is unreachable now. > > IIRC HPET stops in C10 or something stupid like that, I forgot what the > problem with ACPI_PM is.
Yes, that HPET issue is a common one for several generations of client platforms like Baytrail, Coffee Lake etc.
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