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Re: [PATCH v1] Use CLOCK_MONOTONIC_RAW if available for get_clock().
From: |
Joe Tanen |
Subject: |
Re: [PATCH v1] Use CLOCK_MONOTONIC_RAW if available for get_clock(). |
Date: |
Thu, 30 Sep 2021 19:17:48 +0000 |
Peter,
Thanks for the quick response. I've informally socialized the issue and will
update this thread when I get more information.
That aside, I'd find using CLOCK_MONOTONIC_RAW valuable if, e.g., I wanted test
an NTP daemon inside of a guest and didn't want the host providing an
already-adjusted timebase. Would the behavior from my patch be more appropriate
as a command-line option?
v/r
Joe
On 9/30/21, 12:11 PM, "Peter Maydell" <peter.maydell@linaro.org> wrote:
On Thu, 30 Sept 2021 at 17:04, Joe Tanen <jtanen@fb.com> wrote:
>
> CLOCK_MONOTONIC_RAW provides an unadjusted system clock on some platforms,
> which is closer in spirit to providing a guest with a raw hardware clock
than
> CLOCK_MONOTONIC.
>
> Using CLOCK_MONOTONIC_RAW also works around a current issue in OSX where
> CLOCK_MONOTONIC has been observed to go backwards.
>
> Since CLOCK_MONOTONIC_RAW might not be available on all platforms, revert
to
> using CLOCK_MONOTONIC if it is not present.
>
> Signed-off-by: Joe Tanen <jtanen@fb.com>
I'm not sure we want to change behaviour everywhere to work
around an OSX bug, though...
Has this bug been reported to Apple ? Is there some kind of bug
report ID or URL we can quote in the commit message ?
-- PMM