Re: [4.14] Failing selftest timer/adjtick

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