MailboxProcessor perfornance test to compare against the high-performance task-and-channel-based version (separate Gist).

MailboxProcessorPerformanceReference.fs

// MailboxProcessor test for comparison against the performance-optimized task-and-channel-based actor impl. here:
//
// https://gist.github.com/bent-rasmussen/8152df3c842a06acabe219dd877802d5
//
// Tested in LINQPad (hence Dump method usage).

type Message =
    | Incr
    | Not of bool * AsyncReplyChannel<bool>
    | Counter of AsyncReplyChannel<int>
let agent = MailboxProcessor.Start(fun inbox -> 
    let mutable counter = 0
    let rec loop () = async {
        match! inbox.Receive() with
        | Incr -> 
            counter <- counter + 1
        | Not (b, reply) ->
            reply.Reply(not b)
        | Counter ch -> 
            ch.Reply(counter)
        do! loop()
    }
    loop()
)
let clock = Stopwatch.StartNew()
for i = 1 to 1_000_000 do
    agent.Post(Incr)
let elapsed = clock.Elapsed
let counter = agent.PostAndReply(Counter)
counter.Dump("Counter")
clock.Elapsed.TotalSeconds.Dump("Seconds elapsed")

async {
    let clock = Stopwatch.StartNew()
    let mutable b = false
    for i = 1 to 1_000_000 do
        let! b' = agent.PostAndAsyncReply(fun reply -> Not (b, reply))
        b <- b'
    let elapsed = clock.Elapsed
    counter.Dump("b")
    clock.Elapsed.TotalSeconds.Dump("Seconds elapsed")
}
|> Async.RunSynchronously