git: a8b89dff6ac0 - main - Disable acpi_timer_test by default

[John Baldwin]

On 9/7/21 6:32 PM, Colin Percival wrote:
> The branch main has been updated by cperciva:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=a8b89dff6ac026e60983824889d3666842ff409b
> 
> commit a8b89dff6ac026e60983824889d3666842ff409b
> Author:     Colin Percival <cperciva at FreeBSD.org>
> AuthorDate: 2021-09-07 23:59:45 +0000
> Commit:     Colin Percival <cperciva at FreeBSD.org>
> CommitDate: 2021-09-08 01:31:55 +0000
> 
>      Disable acpi_timer_test by default
>      
>      This disables testing the ACPI timer by default, forcing the use of
>      ACPI-fast rather than ACPI-safe.  The broken-ACPI-timers workaround
>      can be re-enabled by setting the hw.acpi.timer_test_enabled=1 tunable.
>      
>      This speeds up the FreeBSD boot process by 140 ms on an EC2 c5.xlarge
>      instance.
>      
>      This change will not be MFCed.
>      
>      Assuming no problems are reported, acpi_timer_test, the associated
>      tunable, and the ACPI-safe timecounter should be removed in FreeBSD 15.
>      
>      Relnotes:       The ACPI-safe timer is disabled in favour of ACPI-fast;
>                      if timekeeping issues are observed, please test with
>                      hw.acpi.timer_test_enabled=1 in loader.conf and report
>                      if that fixes the problem.

Perhaps it should default to '1' for i386 and '0' otherwise?  The relevant
chipsets were 32-bit only, so this would be a simple way to skip the test for
modern hardware, and you could probably MFC that safely.

-- 
John Baldwin