ring threads benchmark async vs hopac job

ring-async.fs

open System
open System.Diagnostics

let ringLength = 503

let cells = Array.zeroCreate ringLength
let threads = Array.zeroCreate ringLength
let answer = ref -1

let createWorker i = 
    let next = (i+1)%ringLength
    async { let value = cells.[i]
            if false then () 
            match value with
            | 0 -> answer := i+1
            | _ -> 
                cells.[next] <- value - 1 
                return! threads.[next] }
    
[<EntryPoint>]
let main args = 
    cells.[0] <- if args.Length>0 then int args.[0] else 50000000
    for i in 0..ringLength-1 do 
        threads.[i]<-createWorker i
    let stopwatch = new Stopwatch()
    stopwatch.Start()
    let result = Async.StartImmediate(threads.[0])
    stopwatch.Stop()
    printfn "%d in %A" !answer stopwatch.Elapsed
    Console.ReadKey() |> ignore
    0

ring-hopac.fs

open System
open System.Diagnostics
open Hopac

let ringLength = 503

let cells = Array.zeroCreate ringLength
let threads : Job<unit>[] = Array.zeroCreate ringLength
let answer = ref -1

let createWorker i = 
    let next = (i+1)%ringLength
    job   { let value = cells.[i]
            if false then () 
            match value with
            | 0 -> answer := i+1
            | _ -> 
                cells.[next] <- value - 1 
                return! threads.[next] }
    
[<EntryPoint>]
let main args = 
    cells.[0] <- if args.Length>0 then int args.[0] else 50000000
    for i in 0..ringLength-1 do 
        threads.[i]<-createWorker i
    let stopwatch = new Stopwatch()
    stopwatch.Start()
    let _ = threads.[0] |> run
    stopwatch.Stop()
    printfn "%d in %A" !answer stopwatch.Elapsed
    Console.ReadKey() |> ignore
    0

But mainly I was inspired by this video https://t.co/x3nGFJDnmm. And decided to check this naive version bacause I think authors of that video uses this kind of thread ring for tests.