IH-628: Add new package for timekeeping #5724

psafont · 2024-06-21T16:38:49Z

Moves Date to be implemented here, without the deprecated functions, and adds the timer module, which should be enough to satisfy the various efforts needing timers

Draft because Tests are missing

clock.opam

ocaml/libs/clock/date.ml

ocaml/libs/clock/timer.ml

Vincent-lau

LGTM, would be good to see how this package is used in xapi

psafont · 2024-06-25T15:16:45Z

ocaml/libs/clock/timer.mli

+
+val span_to_s : Mtime.Span.t -> float
+(** [span_to_s span] converts a time span into seconds, represented by a float.
+    When the span is longer than ~55 years, rounding errors appear. Avoid


Should we add a limit here to 2⁵³ nanoseconds using an option? This would make the conversions symmetric in that respect, and we can treat the error at the caller of the RPC function, and not the callee end.

I have seen the case float -> span -> float for config parsing.

For RPC, it might be that we encounter the case span -> float -> span, so we need to be wary about those. I'll take care of these conversions when I change them.

ocaml/libs/clock/date.ml

ocaml/libs/xapi-stdext/lib/xapi-stdext-date/dune

Signed-off-by: Pau Ruiz Safont <[email protected]>

It currently duplicates the date module from stdext, dropping the deprecated bindings Signed-off-by: Pau Ruiz Safont <[email protected]>

edwintorok

One small change in Dune and rounding, and then it passes the quickcheck on the epoll PR.
(I haven't rebased the entire PR yet, but if the tests pass then the rest should work too)

ocaml/libs/xapi-stdext/lib/xapi-stdext-date/dune

ocaml/libs/clock/timer.ml

Signed-off-by: Pau Ruiz Safont <[email protected]>

This module can be used to know when a certain amount has passed since the timer started by polling. Useful for encoding timeouts, schedule actions periodically and similar. Signed-off-by: Pau Ruiz Safont <[email protected]>

These could help with the porting of the redo_log code, but Edwin's has working code that changes the API of the timed calls to use durations instead of deadlines. Signed-off-by: Pau Ruiz Safont <[email protected]>

Because the debug module doesn't use best practices, pretty-printers using the Format module are not ergonomic to use when they are needed for constructing loglines. Provide a module for adapters, containing Mtime's spans for the time being. Signed-off-by: Pau Ruiz Safont <[email protected]>

This allows to define in the code the exact amount of time, including the measure of time used as base. This is usually minutes. On top of that it allows for two type of configuration parameters: one that retains backwards compatibility, using seconds as floats. They can be used to define relatively short amounts of time (less that 104 days). For longer amounts of time, seconds can be encoded as integers. When printing the configuration, both the literal value used to configure the global and the amount using time units is shown. Signed-off-by: Pau Ruiz Safont <[email protected]>

Signed-off-by: Pau Ruiz Safont <[email protected]>

psafont requested a review from edwintorok June 21, 2024 16:38

Vincent-lau reviewed Jun 21, 2024

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minglumlu reviewed Jun 24, 2024

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