Re: [4.14] Failing selftest timer/adjtick

Joerg Vehlow
2021-03-01T07:06:20Z

Hi Mi

On 2/11/2021 11:59 AM, Miroslav Lichvar wrote:
> I don't think it is specific to arm or that it is a regression. I
> think the virtual machine just happens to be too idle for the test.
> There may be unrelated changes, maybe in the kernel, qemu, or
> applications, that caused the rate of the clock updates to decrease so
> much that the instability now triggers the failure in the test. The
> issue with the clock was there since NO_HZ was introduced, but it
> becomes more severe as the activity of the kernel decreases.
Thanks for the hint towards NO_HZ. Running the tests with some
background load makes them pass reliably.

Jörg