sleep ns julialang

sleep_ns.jl

# adapted from https://github.com/ArchieCall/AccurateSleep/blob/master/src/hybrid_sleep.jl
function sleep_ns(sleep_time::Float64, threshold::Float64 = 0.001)    
    tics_per_sec = 1_000_000_000.0
    nano1 = time_ns()
    nano2 = nano1 + (sleep_time * tics_per_sec)
    
    min_true_sleep = 0.001
    # normal sleep
    if sleep_time > threshold
        actual_sleep_time = max(min_true_sleep, sleep_time - threshold)
        sleep(actual_sleep_time)
    end
    
    # final busy wait
    nano3 = time_ns()
    while true
        nano3 >= nano2 && break
        nano3 = time_ns()
    end
    
    seconds_over = (nano3 - nano2) / tics_per_sec # overshot
    return seconds_over
end

julia> @btime sleep_ns(1e-6)
  1.080 μs (0 allocations: 0 bytes)
8.0e-8

julia> @btime sleep_ns(1e-7)
  269.978 ns (0 allocations: 0 bytes)
1.7e-7

julia> @btime sleep_ns(5e-7)
  539.958 ns (0 allocations: 0 bytes)
4.0e-8

julia> @btime sleep_ns(1e-6)
  1.080 μs (0 allocations: 0 bytes)
8.0e-8

julia> @btime sleep_ns(8e-6)
  8.099 μs (0 allocations: 0 bytes)
9.9e-8

julia> @btime sleep_ns(1e-9)
  269.978 ns (0 allocations: 0 bytes)
2.69e-7