MicroTimer

A timer module with microsend resolution.

MicroTimer can sleep for as low as it takes to the BEAM to send a message (usually 3-5µ).
It can also send messages and invoke functions after a timeout or repeatedly every timeout µs.

Keep in mind that the system sleep primitive literally waits doing nothing, consuming no CPU whatsoever, while µsleep is implemented with message passing and wastes CPU cycles for a maximum of 2ms per call.

The CPU load shouldn't be a problem anyway, but it's definitely non-zero.

Installation

The package can be installed by adding micro_timer to your list of dependencies in mix.exs:

def deps do
  [
    {:micro_timer, "~> 0.1.0"}
  ]
end

API

MicroTimer has a very simple API

• usleep(timeout) and the alias µsleep(timeout)
  sleep for timeout µs.

• apply_after(timeout, executable, args \\ [])
  invoke the executable after timeout µs with the args args
executable can be the tuple {Module, :function} or a function

• apply_every(timeout, executable, args \\ [])
  invoke the executable every timeout µs with the args args

• send_after(timeout, message, pid \\ self())
  send message after timeout µs to pid
  if pid is empty, the message is sento to self()

• send_every(timeout, message, pid \\ self())
  send message every timeout µs to pid

• cancel_timer(timer)
  cancel the timer created by one of apply_after, apply_every, send_after and send_every

*_after and *_avery return a timer reference that is just a regular pid.
You can check if the timer is still active or not with a simple call to Process.alive?(pid)

Basic Usage

iex(1)> :timer.tc(fn -> MicroTimer.usleep(250) end)
{257, :ok}

iex(2)> MicroTimer.send_after(666, :msg)
#PID<0.222.0>
# approximately 666µs later
iex(3)> flush
:msg
:ok

Check out the examples folder in this repository for more realistic examples.

Full documentation can be found at https://hexdocs.pm/micro_timer.

Benchmarks

Google Drive spreadsheet

License

MicroTimer is released under the MIT License - see the LICENSE file.