56e5305 · distributed-process

git.iko.soy/distributed-process

Fix for DP-110. The NC does not block anymore on network operations.

A pool of threads is used for network operations. One thread is used per NodeId. Conflicts: src/Control/Distributed/Process/Internal/Types.hs src/Control/Distributed/Process/Node.hs

commit56e53058be94f581e2af88c85403a35cf6cd40d1 authorFacundo Domínguez <facundo.dominguez@tweag.io> dateThu 23 Apr 2015, 11:25 (11 years ago) parent78ef646

4 files changed+100−2

compare with master

unifiedsplit

distributed-process.cabal+1 src/Control/Distributed/Process/Internal/ThreadPool.hs+78 src/Control/Distributed/Process/Internal/Types.hs+3 src/Control/Distributed/Process/Node.hs+18−2

distributed-process.cabal+1

@@ -68,6 +68,7 @@ Library

6868 Control.Distributed.Process.Internal.StrictContainerAccessors,

6969 Control.Distributed.Process.Internal.StrictList,

7070 Control.Distributed.Process.Internal.StrictMVar,

71+ Control.Distributed.Process.Internal.ThreadPool,

7172 Control.Distributed.Process.Internal.Types,

7273 Control.Distributed.Process.Internal.WeakTQueue,

7374 Control.Distributed.Process.Management,

src/Control/Distributed/Process/Internal/ThreadPool.hsnew file+78

@@ -0,0 +1,78 @@

1+-- | An implementation of a pool of threads

2+--

3+{-# LANGUAGE RecursiveDo #-}

4+module Control.Distributed.Process.Internal.ThreadPool

5+ ( newThreadPool

6+ , submitTask

7+ , lookupWorker

8+ , ThreadPool

9+ ) where

10+

11+import Control.Exception

12+import Control.Monad

13+import Data.IORef

14+import qualified Data.Map as Map

15+

16+

17+-- | A pool of worker threads that execute tasks.

18+--

19+-- Each worker thread is named with a key @k@. Tasks are submitted to a

20+-- specific worker using its key. While the worker is busy the tasks are queued.

21+-- When there are no more queued tasks the worker ceases to exist.

22+--

23+-- The next time a task is submitted the worker will be respawned.

24+--

25+newtype ThreadPool k w = ThreadPool (IORef (Map.Map k (Maybe (IO ()), w)))

26+

27+-- Each worker has an entry in the map with a closure that contains all

28+-- queued actions fot it.

29+--

30+-- No entry in the map is kept for defunct workers.

31+

32+-- | Creates a pool with no workers.

33+newThreadPool :: IO (ThreadPool k w)

34+newThreadPool = fmap ThreadPool $ newIORef Map.empty

35+

36+-- | @submitTask pool fork k task@ submits a task for the worker @k@.

37+--

38+-- If worker @k@ is busy, then the task is queued until the worker is available.

39+--

40+-- If worker @k@ does not exist, then the given @fork@ operation is used to

41+-- spawn the worker. @fork@ returns whatever information is deemed useful for

42+-- later retrieval via 'lookupWorker'.

43+--

44+submitTask :: Ord k

45+ => ThreadPool k w

46+ -> (IO () -> IO w)

47+ -> k -> IO () -> IO ()

48+submitTask (ThreadPool mapRef) fork k task = mdo

49+ m' <- join $ atomicModifyIORef mapRef $ \m ->

50+ case Map.lookup k m of

51+ -- There is no worker for this key, create one.

52+ Nothing -> ( m'

53+ , do w <- fork $ flip onException terminateWorker $ do

54+ task

55+ continue

56+ return $ Map.insert k (Nothing, w) m

57+ )

58+ -- Queue an action for the existing worker.

59+ Just (mp, w) ->

60+ (m', return $ Map.insert k (Just $ maybe task (>> task) mp, w) m)

61+ return ()

62+ where

63+ continue = join $ atomicModifyIORef mapRef $ \m ->

64+ case Map.lookup k m of

65+ -- Execute the next batch of queued actions.

66+ Just (Just p, w) -> (Map.insert k (Nothing, w) m, p >> continue)

67+ -- There are no more queued actions. Terminate the worker.

68+ Just (Nothing, w) -> (Map.delete k m, return ())

69+ -- The worker key was removed already (?)

70+ Nothing -> (m, return ())

71+ -- Remove the worker key regardless of whether there are more queued

72+ -- actions.

73+ terminateWorker = atomicModifyIORef mapRef $ \m -> (Map.delete k m, ())

74+

75+-- | Looks up a worker with the given key.

76+lookupWorker :: Ord k => ThreadPool k w -> k -> IO (Maybe w)

77+lookupWorker (ThreadPool mapRef) k =

78+ atomicModifyIORef mapRef $ \m -> (m, fmap snd $ Map.lookup k m)

src/Control/Distributed/Process/Internal/Types.hs+3

@@ -137,6 +137,7 @@ import Control.Distributed.Process.Internal.StrictMVar

137137 , modifyMVar

138138 , modifyMVar_

139139 )

140+import Control.Distributed.Process.Internal.ThreadPool

140141import Control.Distributed.Process.Internal.WeakTQueue (TQueue)

141142import Control.Distributed.Static (RemoteTable, Closure)

142143import qualified Control.Distributed.Process.Internal.StrictContainerAccessors as DAC (mapMaybe)

@@ -267,6 +268,8 @@ data LocalNode = LocalNode

267268 -- | Runtime lookup table for supporting closures

268269 -- TODO: this should be part of the CH state, not the local endpoint state

269270 , remoteTable :: !RemoteTable

271+ -- The pool of threads and queues to send messages

272+ , localSendPool :: ThreadPool NodeId ThreadId

270273 }

271274

272275data ImplicitReconnect = WithImplicitReconnect | NoImplicitReconnect

src/Control/Distributed/Process/Node.hs+18−2

@@ -91,6 +91,12 @@ import Control.Distributed.Process.Internal.StrictMVar

9191 , putMVar

9292 , takeMVar

9393 )

94+import Control.Distributed.Process.Internal.ThreadPool

95+ ( newThreadPool

96+ , submitTask

97+ , lookupWorker

98+ , ThreadPool

99+ )

94100import Control.Concurrent.Chan (newChan, writeChan, readChan)

95101import qualified Control.Concurrent.MVar as MVar (newEmptyMVar, takeMVar)

96102import Control.Concurrent.STM

@@ -264,12 +270,14 @@ createBareLocalNode endPoint rtable = do

264270 , _localConnections = Map.empty

265271 }

266272 ctrlChan <- newChan

273+ sendPool <- newThreadPool

267274 let node = LocalNode { localNodeId = NodeId $ NT.address endPoint

268275 , localEndPoint = endPoint

269276 , localState = state

270277 , localCtrlChan = ctrlChan

271278 , localEventBus = MxEventBusInitialising

272279 , remoteTable = rtable

280+ , localSendPool = sendPool

273281 }

274282 tracedNode <- startMxAgent node

275283

@@ -613,6 +621,8 @@ handleIncomingMessages node = go initConnectionState

613621 , ctrlMsgSignal = Died nid DiedDisconnect

614622 }

615623 let notLost k = not (k `Set.member` (st ^. incomingFrom theirAddr))

624+ liftIO $ lookupWorker (localSendPool node) (NodeId theirAddr)

625+ >>= maybe (return ()) killThread

616626 closeImplicitReconnections node nid

617627 go ( (incomingFrom theirAddr ^= Set.empty)

618628 . (incoming ^: Map.filterWithKey (const . notLost))

@@ -669,6 +679,12 @@ data NCState = NCState

669679 , _registeredOnNodes :: !(Map ProcessId [(NodeId,Int)])

670680 }

671681

682+submitSendPool :: LocalNode -> NodeId -> IO () -> IO ()

683+submitSendPool node nid task = submitTask (localSendPool node) fork nid task

684+ where

685+ fork io =

686+ forkIO $ io `Exception.catch` \(NodeClosedException _) -> return ()

687+

672688newtype NC a = NC { unNC :: StateT NCState (ReaderT LocalNode IO) a }

673689 deriving ( Applicative

674690 , Functor

@@ -704,7 +720,7 @@ ncSendToProcessAndTrace shouldTrace pid msg = do

704720 node <- ask

705721 if processNodeId pid == localNodeId node

706722 then ncEffectLocalSendAndTrace shouldTrace node pid msg

707− else liftIO $ sendBinary node

723+ else liftIO $ submitSendPool node (processNodeId pid) $ sendBinary node

708724 (NodeIdentifier $ localNodeId node)

709725 (NodeIdentifier $ processNodeId pid)

710726 WithImplicitReconnect

@@ -717,7 +733,7 @@ ncSendToNode to msg = do

717733 node <- ask

718734 liftIO $ if to == localNodeId node

719735 then writeChan (localCtrlChan node) $! msg

720− else sendBinary node

736+ else submitSendPool node to $ sendBinary node

721737 (NodeIdentifier $ localNodeId node)

722738 (NodeIdentifier to)

723739 WithImplicitReconnect