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|
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE DoAndIfThenElse #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE RecordWildCards #-}
-------------------------------------------------------------------------------
-- |
-- Module : GHC.Event.Windows.ManagedThreadPool
-- Copyright : (c) Tamar Christina 2019
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
-- Portability : non-portable
--
-- WinIO Windows Managed Thread pool API. This thread pool scales dynamically
-- based on demand.
--
-------------------------------------------------------------------------------
module GHC.Event.Windows.ManagedThreadPool
( ThreadPool(..)
, startThreadPool
, notifyRunning
, notifyWaiting
, monitorThreadPool
) where
import Control.Concurrent.MVar
import Data.Maybe
import Foreign
import GHC.Base
import GHC.Num ((-), (+))
import GHC.Real (fromIntegral)
import qualified GHC.Event.Array as A
import GHC.IO.Handle.Internals (debugIO)
import GHC.Conc.Sync (ThreadId(..))
import GHC.RTS.Flags
------------------------------------------------------------------------
-- Thread spool manager
type WorkerJob = IO ()
-- | Thread pool manager state
data ThreadPool = ThreadPool
{ thrMainThread :: Maybe ThreadId
, thrMaxThreads :: {-# UNPACK #-} !Int
, thrMinThreads :: {-# UNPACK #-} !Int
, thrCurThreads :: {-# UNPACK #-} !Int
, thrCallBack :: WorkerJob
, thrActiveThreads :: MVar Int
, thrMonitor :: MVar ()
, thrThreadIds :: {-#UNPACK #-} !(A.Array ThreadId)
}
startThreadPool :: WorkerJob -> IO ThreadPool
startThreadPool job = do
debugIO "Starting I/O manager threadpool..."
let thrMinThreads = 2
let thrCurThreads = 0
let thrCallBack = job
thrMaxThreads <- (fromIntegral . numIoWorkerThreads) `fmap` getMiscFlags
thrActiveThreads <- newMVar 0
thrMonitor <- newEmptyMVar
thrThreadIds <- undefined -- A.new thrMaxThreads
let thrMainThread = Nothing
let !pool = ThreadPool{..}
return pool
monitorThreadPool :: MVar () -> IO ()
monitorThreadPool monitor = do
_active <- takeMVar monitor
return ()
notifyRunning :: Maybe ThreadPool -> IO ()
notifyRunning Nothing = return ()
notifyRunning (Just pool) = do
modifyMVar_ (thrActiveThreads pool) (\x -> return $ x + 1)
_ <- tryPutMVar (thrMonitor pool) ()
return ()
notifyWaiting :: Maybe ThreadPool -> IO ()
notifyWaiting Nothing = return ()
notifyWaiting (Just pool) = do
modifyMVar_ (thrActiveThreads pool) (\x -> return $ x - 1)
_ <- tryPutMVar (thrMonitor pool) ()
return ()
|
