Re: [PATCH resend] clocksource: Defer override invalidation unless clock is unstable

From: Kyle Walker
Date: Fri Aug 05 2016 - 14:39:46 EST


Good evening John,

On Wed, Jul 27, 2016 at 10:29 AM, Kyle Walker <kwalker@xxxxxxxxxx> wrote:
> The issue I'm running into is that the override is not HRT compatible yet.
> Though it will be later in the boot process, unless the clocksource watchdog
> marks the clocksource as unstable.
>
> The issue with the current implementation is that the override_name value is
> disabled when the tsc is first checked, before the watchdog has a chance to
> check it and mark it stable or unstable.
>
> Without patch:
> $ dmesg | grep -e clocksource
> <snip>
> clocksource: refined-jiffies: <snip>
> Kernel command line: <snip> clocksource=tsc
> clocksource: hpet: <snip>
> clocksource: xen: <snip>
> clocksource: jiffies: <snip>
> clocksource: Switched to clocksource xen
> clocksource: acpi_pm: <snip>
> tsc: Refined TSC clocksource calibration: 2394.399 MHz
>
> clocksource: tsc: <snip>
> clocksource: Override clocksource tsc is not HRT compatible - <snip>
>
>
> With patch:
> $ dmesg | grep -e clocksource
> <snip>
> clocksource: refined-jiffies:<snip>
> Kernel command line: <snip> clocksource=tsc
> clocksource: hpet: <snip>
> clocksource: xen: <snip>
>
> clocksource: jiffies: <snip>
> clocksource: Switched to clocksource xen
> clocksource: acpi_pm: <snip>
> tsc: Refined TSC clocksource calibration: 2394.461 MHz
> clocksource: tsc: <snip>
> clocksource: Override clocksource tsc is not currently HRT compatible
> - deferring
> clocksource: Switched to clocksource tsc
>

Is there anything else needed from my end? Please let me know if there is
any further information or clarification I can provide.

Have a great evening!
--
Kyle Walker