Re: [PATCH 2/3 v3] time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting

From: Miroslav Lichvar
Date: Tue Jun 13 2017 - 06:30:37 EST


On Thu, Jun 08, 2017 at 04:44:21PM -0700, John Stultz wrote:
> Due to how the MONOTONIC_RAW accumulation logic was handled,
> there is the potential for a 1ns discontinuity when we do
> accumulations. This small discontinuity has for the most part
> gone un-noticed, but since ARM64 enabled CLOCK_MONOTONIC_RAW
> in their vDSO clock_gettime implementation, we've seen failures
> with the inconsistency-check test in kselftest.
>
> This patch addresses the issue by using the same sub-ns
> accumulation handling that CLOCK_MONOTONIC uses, which avoids
> the issue for in-kernel users.

The patch looks good to me and in testing on x86_64 I didn't see any
issues with the CLOCK_MONOTONIC_RAW clock.

Thanks,

--
Miroslav Lichvar