From 82fa6480de7a85d0ced0701ab7c8825e31b90770 Mon Sep 17 00:00:00 2001 From: Jo-Philipp Wich Date: Sun, 15 Oct 2023 00:17:36 +0200 Subject: uloop: add support for interval timers So far, the only way to implement periodic interval timers was to use one-shot uloop_timeout timers which are rearmed within their completion callback immediately on expiration. While simple, this approach is not very precise and interval lengths will slowly drift over time, due to callback execution overhead, scheduling granularity etc. In order to make uloop provide stable and precise interval timer capabilities, this commit introduces a new `uloop_interval` structure along with the new related `uloop_interval_set()`, `uloop_interval_cancel()` and `uloop_interval_remaining()` api functions. Periodic timers are implemented using the timerfd facility an Linux and kqueue EVFILT_TIMER events on macOS/BSD. The Lua binding has been updated to include support for the new timer type as well. Signed-off-by: Jo-Philipp Wich --- examples/uloop-example.lua | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'examples') diff --git a/examples/uloop-example.lua b/examples/uloop-example.lua index 511b9ea..f3aef60 100755 --- a/examples/uloop-example.lua +++ b/examples/uloop-example.lua @@ -24,6 +24,23 @@ uloop.timer(function() print("2000 ms timer run"); end, 2000) -- timer example 3 (will never run) uloop.timer(function() print("3000 ms timer run"); end, 3000):cancel() +-- periodic interval timer +local intv +intv = uloop.interval(function() + print(string.format("Interval expiration #%d - %dms until next expiration", + intv:expirations(), intv:remaining())) + + -- after 5 expirations, lower interval to 500ms + if intv:expirations() >= 5 then + intv:set(500) + end + + -- cancel after 10 expirations + if intv:expirations() >= 10 then + intv:cancel() + end +end, 1000) + -- process function p1(r) print("Process 1 completed") -- cgit v1.2.3