在异步工作流中并行运行函数

Question

以下代码

let doWork n = async {
    [1..5]
    |> Seq.iter(fun i ->
        System.Threading.Thread.Sleep 1000 // Simulate working
        printfn "%s runs %i seconds" n i
        )
}
let f1 = async {
    do! doWork "f1"
    return 1
}
async {
    let a = f1
    do! doWork "main"
    let! i = a
} |> Async.RunSynchronously

它打印以下结果。它显示两个doWork调用按顺序运行。

main runs 1 seconds
main runs 2 seconds
main runs 3 seconds
main runs 4 seconds
main runs 5 seconds
f1 runs 1 seconds
f1 runs 2 seconds
f1 runs 3 seconds
f1 runs 4 seconds
f1 runs 5 seconds

但是，我希望f1调用的doWork和主代码并行运行？

Answer 1

像这样尝试：

let computation () = async {
  printfn "Start work"
  do! Async.Sleep(100)
  printfn "Finished work"
}
let s = seq {
  for i in 1 .. 10 do
    let c = computation()
    yield c
}
s |> Async.Parallel |> Async.Ignore |> Async.Start

Async.Parallel将Async<unit> list转换为可以并行运行的Async<unit []>。