在玩过 F# 代理后，我尝试使用它们来减少地图。
我使用的基本结构是：
- 地图主管将所有工作排队在其状态下完成并接收来自地图工作人员的工作请求
- reduce 主管与 map 主管做同样的事情来减少工作
- 一组 map 和 reduce 工作人员，如果其中一个工作失败，则将其发送回各自的主管进行重新处理。
我想知道的问题是：
- 与使用 PSeq 的更传统（但非常好）的 map reduce （http://tomasp.net/blog/fsharp-parallel-aggregate.aspx）相比，这是否有意义？
- 我实现地图和减少工人的方式看起来很丑，有没有更好的方法？
- 好像我可以创建一个 1000 000 地图工人和 1000 0000 减少工人大声笑，我应该如何选择这些数字，越多越好？
非常感谢，
type Agent<'T> = MailboxProcessor<'T>
//This is the response the supervisor
//gives to the worker request for work
type 'work SupervisorResponse =
| Work of 'work //a piece of work
| NoWork//no work left to do
//This is the message to the supervisor
type 'work WorkMsg =
| ToDo of 'work //piles up work in the Supervisor queue
| WorkReq of AsyncReplyChannel<SupervisorResponse<'work>> //'
//The supervisor agent can be interacted with
type AgentOperation =
| Stop //stop the agent
| Status //yield the current status of supervisor
type 'work SupervisorMsg =
| WorkRel of 'work WorkMsg
| Operation of AgentOperation
//Supervises Map and Reduce workers
module AgentSupervisor=
let getNew (name:string) =
new Agent<SupervisorMsg<'work>>(fun inbox -> //'
let rec loop state = async {
let! msg = inbox.Receive()
match msg with
| WorkRel(m) ->
match m with
| ToDo(work) ->
let newState = work:state
return! loop newState
| WorkReq(replyChannel) ->
match state with
| [] ->
replyChannel.Reply(NoWork)
return! loop []
| [item] ->
replyChannel.Reply(Work(item))
return! loop []
| (item::remaining) ->
replyChannel.Reply(Work(item))
return! loop remaining
| Operation(op) ->
match op with
| Status ->
Console.WriteLine(name+" current Work Queue "+
string (state.Length))
return! loop state
| Stop ->
Console.WriteLine("Stoppped SuperVisor Agent "+name)
return()
}
loop [] )
let stop (agent:Agent<SupervisorMsg<'work>>) = agent.Post(Operation(Stop))
let status (agent:Agent<SupervisorMsg<'work>>) =agent.Post(Operation(Status))
//Code for the workers
type 'success WorkOutcome =
| Success of 'success
| Fail
type WorkerMsg =
| Start
| Stop
| Continue
module AgentWorker =
type WorkerSupervisors<'reduce,'work> =
{ Map:Agent<SupervisorMsg<'work>> ; Reduce:Agent<SupervisorMsg<'reduce>> }
let stop (agent:Agent<WorkerMsg>) = agent.Post(Stop)
let start (agent:Agent<WorkerMsg>) = agent.Start()
agent.Post(Start)
let getNewMapWorker( map, supervisors:WorkerSupervisors<'reduce,'work> ) =
new Agent<WorkerMsg>(fun inbox ->
let rec loop () = async {
let! msg = inbox.Receive()
match msg with
| Start -> inbox.Post(Continue)
return! loop ()
| Continue ->
let! supervisorOrder =
supervisors.Map.PostAndAsyncReply(
fun replyChannel ->
WorkRel(WorkReq(replyChannel)))
match supervisorOrder with
| Work(work) ->
let! res = map work
match res with
| Success(toReduce) ->
supervisors.Reduce
.Post(WorkRel(ToDo(toReduce)))
| Fail ->
Console.WriteLine("Map Fail")
supervisors.Map
.Post(WorkRel(ToDo(work)))
inbox.Post(Continue)
| NoWork ->
inbox.Post(Continue)
return! loop ()
| Stop ->
Console.WriteLine("Map worker stopped")
return ()
}
loop () )
let getNewReduceWorker(reduce,reduceSupervisor:Agent<SupervisorMsg<'work>>)=//'
new Agent<WorkerMsg>(fun inbox ->
let rec loop () = async {
let! msg = inbox.Receive()
match msg with
| Start -> inbox.Post(Continue)
return! loop()
| Continue ->
let! supervisorOrder =
reduceSupervisor.PostAndAsyncReply(fun replyChannel ->
WorkRel(WorkReq(replyChannel)))
match supervisorOrder with
| Work(work) ->
let! res = reduce work
match res with
| Success(toReduce) -> inbox.Post(Continue)
| Fail ->
Console.WriteLine("ReduceFail")
reduceSupervisor.Post(WorkRel(ToDo(work)))
inbox.Post(Continue)
| NoWork -> inbox.Post(Continue)
return! loop()
|Stop ->Console.WriteLine("Reduce worker stopped"); return ()
}
loop() )
open AgentWorker
type MapReduce<'work,'reduce>( numberMap:int ,
numberReduce: int,
toProcess:'work list,
map:'work->Async<'reduce WorkOutcome>,
reduce:'reduce-> Async<unit WorkOutcome>) =
let mapSupervisor= AgentSupervisor.getNew("MapSupervisor")
let reduceSupervisor = AgentSupervisor.getNew("ReduceSupervisor")
let workerSupervisors = {Map = mapSupervisor ; Reduce = reduceSupervisor }
let mapWorkers =
[for i in 1..numberMap ->
AgentWorker.getNewMapWorker(map,workerSupervisors) ]
let reduceWorkers =
[for i in 1..numberReduce ->
AgentWorker.getNewReduceWorker(reduce,workerSupervisors.Reduce) ]
member this.Start() =
//Post work to do
toProcess
|>List.iter(fun elem -> mapSupervisor.Post( WorkRel(ToDo(elem))))
//Start supervisors
mapSupervisor.Start()
reduceSupervisor.Start()
//start workers
List.iter( fun mapper -> mapper |>start) mapWorkers
List.iter( fun reducer ->reducer|>start) reduceWorkers
member this.Status() = (mapSupervisor|>AgentSupervisor.status)
(reduceSupervisor|>AgentSupervisor.status)
member this.Stop() =
List.map2(fun mapper reducer ->
mapper |>stop; reducer|>stop) mapWorkers reduceWorkers
//Run some tests
let map = function (n:int64) -> async{ return Success(n) }
let reduce = function (toto: int64) -> async{ return Success() }
let mp = MapReduce<int64,int64>( 1,1,[for i in 1L..1000000L->i],map,reduce)
mp.Start()
mp.Status()
mp.Stop()