Re: Monotonic clock

"Eugene Zaikonnikov (as ez at norphonic dot com)" <[email protected]>
Newsgroups gmane.lisp.lispworks.general
Message-ID <[email protected]>
Tim Bradshaw <[email protected]> writes:

[...]

> Probably not.  Monotonic time means that even if someone screws around
> with the system's clock the numbers will increase.

Exactly. It's hardly an issue for most practical uses but when you have
a system with continuous time synchronization things become wonky. Stuff
like rate limters, watchdog monitors and probably countless other
popular libraries (e.g. see WAIT-FOR-INPUT in usocket) start to fail
subtly.

> It might be that CL implementations (LW in particular) do use a
> monotonic clock for get-internal-real-time but I would not be
> surprised if some do not.
>
LW 8 on arm32 appears not to. CCL has monotonic source by default, and
SBCL appears to use coarse monotonic clock on most Linux builds (but not
some other platforms).

-- 
Regards,

  Eugene Zaikonnikov

  Norphonic AS
  Tel: +47 98 23 97 73

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