{-# LANGUAGE RankNTypes, NamedFieldPuns, BangPatterns,
             ExistentialQuantification, CPP, ScopedTypeVariables,
             TypeSynonymInstances, MultiParamTypeClasses,
             GeneralizedNewtypeDeriving, PackageImports,
             ParallelListComp #-}


{- OPTIONS_GHC -Wall -fno-warn-name-shadowing -fno-warn-unused-do-bind -}

-- {- LANGUAGE Trustworthy -}
-- TODO: Before declaring this module TRUSTWORTHY/SAFE, we need to
-- make the IVar type abstract.

{-# LANGUAGE TypeFamilies #-}

-- | A scheduler for the Par monad based on directly performing IO
-- actions when Par methods are called (i.e. without using a lazy
-- trace data structure).

module Control.Monad.Par.Scheds.Direct (
   Sched(..),
   Par, -- abstract: Constructor not exported.
   IVar(..), IVarContents(..),
--    sched,
    runPar, runParIO,
    new, get, put_, fork,
    newFull, newFull_, put,
    spawn, spawn_, spawnP,
    spawn1_, fixPar, FixParException (..)
--   runParAsync, runParAsyncHelper,
--   yield,
 ) where

import Control.Applicative
import Control.Concurrent hiding (yield)
import Data.IORef         (IORef,newIORef,readIORef,writeIORef,atomicModifyIORef)
import Text.Printf        (printf)
import GHC.Conc           (numCapabilities,yield)
import Control.Monad
import Control.Monad.IO.Class
import Control.Monad.Trans
import           "mtl" Control.Monad.Cont as C
import qualified "mtl" Control.Monad.Reader as RD
import qualified       System.Random.MWC as Random
import                 System.IO.Unsafe (unsafePerformIO)
import                 System.Mem.StableName (makeStableName, hashStableName)
import qualified       Control.Monad.Par.Class  as PC
import qualified       Control.Monad.Par.Unsafe as UN
import                 Control.Monad.Par.Scheds.DirectInternal
                       (Par(..), Sched(..), HotVar, SessionID, Session(Session),
                        newHotVar, readHotVar, modifyHotVar, modifyHotVar_,
                        writeHotVarRaw, fixPar, FixParException (..))
#ifdef NEW_GENERIC
import qualified       Control.Par.Class as PN
import qualified       Control.Par.Class.Unsafe as PU
#endif
import Control.DeepSeq
#ifdef NESTED_SCHEDS
import qualified Data.Map as M
#endif
import qualified Data.Set as S
import Data.Maybe (catMaybes)
import Data.Word (Word64)

-- import Data.Concurrent.Deque.Class (WSDeque)
#ifdef USE_CHASELEV
#warning "Note: using Chase-Lev lockfree workstealing deques..."
import Data.Concurrent.Deque.ChaseLev.DequeInstance
import Data.Concurrent.Deque.ChaseLev as R
#else
import Data.Concurrent.Deque.Reference.DequeInstance
import Data.Concurrent.Deque.Reference as R
#endif

import qualified Control.Exception as E

import Prelude hiding (null)
import qualified Prelude

#if __GLASGOW_HASKELL__ <= 700
import GHC.Conc (forkOnIO)
forkOn = forkOnIO
#endif

--------------------------------------------------------------------------------
-- Configuration Toggles
--------------------------------------------------------------------------------

-- [2012.08.30] This shows a 10X improvement on nested parfib:
-- #define NESTED_SCHEDS
#define PARPUTS
#define FORKPARENT
#define IDLING_ON
   -- Next, IF idling is on, should we do wakeups?:
#define WAKEIDLE

-- #define WAIT_FOR_WORKERS

-------------------------------------------------------------------
-- Ifdefs for the above preprocessor defines.  Try to MINIMIZE code
-- that lives in this dangerous region, and instead do normal
-- conditionals and trust dead-code-elimination.
--------------------------------------------------------------------

#ifdef DEBUG_DIRECT
#warning "DEBUG: Activating debugging for Direct.hs"
import Debug.Trace        (trace)
import System.Environment (getEnvironment)
theEnv = unsafePerformIO $ getEnvironment
dbg = True
dbglvl = 1
#else
dbg :: Bool
dbg = Bool
False
dbglvl :: Int
dbglvl = Int
0
#endif
dbg    :: Bool
dbglvl :: Int

_PARPUTS :: Bool
#ifdef PARPUTS
_PARPUTS :: Bool
_PARPUTS = Bool
True
#else
_PARPUTS = False
#endif

_FORKPARENT :: Bool
#ifdef FORKPARENT
_FORKPARENT :: Bool
_FORKPARENT = Bool
True
#else
#warning "FORKPARENT POLICY NOT USED; THIS IS GENERALLY WORSE"
_FORKPARENT = False
#endif

_IDLING_ON :: Bool
#ifdef IDLING_ON
_IDLING_ON :: Bool
_IDLING_ON = Bool
True
#else
_IDLING_ON = False
#endif

_WAIT_FOR_WORKERS :: Bool
#ifdef WAIT_FOR_WORKERS
_WAIT_FOR_WORKERS = True
#else
_WAIT_FOR_WORKERS :: Bool
_WAIT_FOR_WORKERS = Bool
False
#endif



--------------------------------------------------------------------------------
-- Core type definitions
--------------------------------------------------------------------------------

type ROnly = RD.ReaderT Sched IO

newtype IVar a = IVar (IORef (IVarContents a))

data IVarContents a = Full a | Empty | Blocked [a -> IO ()]

unsafeParIO :: IO a -> Par a
unsafeParIO :: forall a. IO a -> Par a
unsafeParIO IO a
iom = ContT () (ReaderT Sched IO) a -> Par a
forall a. ContT () (ReaderT Sched IO) a -> Par a
Par (ROnly a -> ContT () (ReaderT Sched IO) a
forall (m :: * -> *) a. Monad m => m a -> ContT () m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift(ROnly a -> ContT () (ReaderT Sched IO) a)
-> ROnly a -> ContT () (ReaderT Sched IO) a
forall a b. (a -> b) -> a -> b
$ IO a -> ROnly a
forall (m :: * -> *) a. Monad m => m a -> ReaderT Sched m a
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
lift IO a
iom)

io :: IO a -> Par a
io :: forall a. IO a -> Par a
io = IO a -> Par a
forall a. IO a -> Par a
unsafeParIO -- shorthand used below

--------------------------------------------------------------------------------
-- Global State
--------------------------------------------------------------------------------

-- This keeps track of ALL worker threads across all unreated
-- `runPar` instantiations.  This is used to detect nested invocations
-- of `runPar` and avoid reinitialization.
-- globalWorkerPool :: IORef (Data.IntMap ())
#ifdef NESTED_SCHEDS
globalWorkerPool :: IORef (M.Map ThreadId Sched)
globalWorkerPool = unsafePerformIO $ newIORef M.empty
#endif
-- TODO! Make this semi-local! (not shared between "top-level" runPars)

{-# INLINE amINested #-}
{-# INLINE registerWorker #-}
{-# INLINE unregisterWorker #-}
amINested :: ThreadId -> IO (Maybe Sched)
registerWorker :: ThreadId -> Sched -> IO ()
unregisterWorker :: ThreadId -> IO ()
#ifdef NESTED_SCHEDS
-- | If the current threadID is ALREADY a worker, return the corresponding Sched structure.
amINested tid = do
  -- There is no race here.  Each thread inserts itself before it
  -- becomes an active worker.
  wp <- readIORef globalWorkerPool
  return (M.lookup tid wp)
registerWorker tid sched =
  atomicModifyIORef globalWorkerPool $
    \ mp -> (M.insert tid sched mp, ())
unregisterWorker tid =
  atomicModifyIORef globalWorkerPool $
    \ mp -> (M.delete tid mp, ())
#else
amINested :: ThreadId -> IO (Maybe Sched)
amINested      ThreadId
_      = Maybe Sched -> IO (Maybe Sched)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe Sched
forall a. Maybe a
Nothing
registerWorker :: ThreadId -> Sched -> IO ()
registerWorker ThreadId
_ Sched
_    = () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
unregisterWorker :: ThreadId -> IO ()
unregisterWorker ThreadId
_tid = () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
#endif

-----------------------------------------------------------------------------
-- Helpers #2:  Pushing and popping work.
-----------------------------------------------------------------------------

{-# INLINE popWork  #-}
popWork :: Sched -> IO (Maybe (Par ()))
popWork :: Sched -> IO (Maybe (Par ()))
popWork Sched{ WSDeque (Par ())
workpool :: WSDeque (Par ())
workpool :: Sched -> WSDeque (Par ())
workpool, Int
no :: Int
no :: Sched -> Int
no } = do
  mb <- SimpleDeque (Par ()) -> IO (Maybe (Par ()))
forall a. SimpleDeque a -> IO (Maybe a)
R.tryPopL WSDeque (Par ())
SimpleDeque (Par ())
workpool
  when dbg $ case mb of
         Maybe (Par ())
Nothing -> () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
         Just Par ()
_  -> do sn <- Maybe (Par ()) -> IO (StableName (Maybe (Par ())))
forall a. a -> IO (StableName a)
makeStableName Maybe (Par ())
mb
                       printf " [%d]                                   -> POP work unit %d\n" no (hashStableName sn)
  return mb

{-# INLINE pushWork #-}
pushWork :: Sched -> Par () -> IO ()
pushWork :: Sched -> Par () -> IO ()
pushWork Sched { WSDeque (Par ())
workpool :: Sched -> WSDeque (Par ())
workpool :: WSDeque (Par ())
workpool, HotVar [MVar Bool]
idle :: HotVar [MVar Bool]
idle :: Sched -> HotVar [MVar Bool]
idle, Int
no :: Sched -> Int
no :: Int
no } Par ()
task = do
  SimpleDeque (Par ()) -> Par () -> IO ()
forall t. SimpleDeque t -> t -> IO ()
R.pushL WSDeque (Par ())
SimpleDeque (Par ())
workpool Par ()
task
  Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg (IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ do sn <- Par () -> IO (StableName (Par ()))
forall a. a -> IO (StableName a)
makeStableName Par ()
task
                printf " [%d]                                   -> PUSH work unit %d\n" no (hashStableName sn)
#if  defined(IDLING_ON) && defined(WAKEIDLE)
  --when isMain$    -- Experimenting with reducing contention by doing this only from a single thread.
                    -- TODO: We need to have a proper binary wakeup-tree.
  HotVar [MVar Bool] -> IO ()
tryWakeIdle HotVar [MVar Bool]
idle
#endif
  () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

tryWakeIdle :: HotVar [MVar Bool] -> IO ()
tryWakeIdle :: HotVar [MVar Bool] -> IO ()
tryWakeIdle HotVar [MVar Bool]
idle = do
-- NOTE: I worry about having the idle var hammered by all threads on their spawn-path:
  -- If any worker is idle, wake one up and give it work to do.
  idles <- HotVar [MVar Bool] -> IO [MVar Bool]
forall a. HotVar a -> IO a
readHotVar HotVar [MVar Bool]
idle -- Optimistically do a normal read first.
  when (not (Prelude.null idles)) $ do
    when dbg$ printf "Waking %d idle thread(s).\n" (length idles)
    r <- modifyHotVar idle (\[MVar Bool]
is -> case [MVar Bool]
is of
                             []      -> ([], () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ())
                             (MVar Bool
i:[MVar Bool]
ils) -> ([MVar Bool]
ils, MVar Bool -> Bool -> IO ()
forall a. MVar a -> a -> IO ()
putMVar MVar Bool
i Bool
False))
    r -- wake an idle worker up by putting an MVar.

rand :: HotVar Random.GenIO -> IO Int
rand :: HotVar GenIO -> IO Int
rand HotVar GenIO
ref = (Int, Int) -> GenIO -> IO Int
forall a (m :: * -> *).
(Variate a, PrimMonad m) =>
(a, a) -> Gen (PrimState m) -> m a
forall (m :: * -> *).
PrimMonad m =>
(Int, Int) -> Gen (PrimState m) -> m Int
Random.uniformR (Int
0, Int
numCapabilitiesInt -> Int -> Int
forall a. Num a => a -> a -> a
-Int
1) (Gen RealWorld -> IO Int) -> IO (Gen RealWorld) -> IO Int
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< HotVar (Gen RealWorld) -> IO (Gen RealWorld)
forall a. HotVar a -> IO a
readHotVar HotVar (Gen RealWorld)
HotVar GenIO
ref

--------------------------------------------------------------------------------
-- Running computations in the Par monad
--------------------------------------------------------------------------------

instance NFData (IVar a) where
  rnf :: IVar a -> ()
rnf !IVar a
_ = ()

{-# NOINLINE runPar #-}
runPar :: forall a. Par a -> a
runPar = IO a -> a
forall a. IO a -> a
unsafePerformIO (IO a -> a) -> (Par a -> IO a) -> Par a -> a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Par a -> IO a
forall a. Par a -> IO a
runParIO


-- | This procedure creates a new worker on the current thread (with a
--   new session ID) and plugs it into the work-stealing environment.
--   This new worker extracts itself from the work stealing pool when
--   `userComp` has completed, thus freeing the current thread (this
--   procedure) to return normally.
runNewSessionAndWait :: String -> Sched -> Par b -> IO b
runNewSessionAndWait :: forall b. String -> Sched -> Par b -> IO b
runNewSessionAndWait String
name Sched
sched Par b
userComp = do
    tid <- IO ThreadId
myThreadId -- TODO: remove when done debugging
    sid <- modifyHotVar (sessionCounter sched) (\ SessionID
x -> (SessionID
xSessionID -> SessionID -> SessionID
forall a. Num a => a -> a -> a
+SessionID
1,SessionID
x))
    _ <- modifyHotVar (activeSessions sched) (\ Set SessionID
set -> (SessionID -> Set SessionID -> Set SessionID
forall a. Ord a => a -> Set a -> Set a
S.insert SessionID
sid Set SessionID
set, ()))

    -- Here we have an extra IORef... ugly.
    ref <- newIORef (error$ "Empty session-result ref ("++name++") should never be touched (sid "++ show sid++", "++show tid ++")")
    newFlag <- newHotVar False
    -- Push the new session:
    _ <- modifyHotVar (sessions sched) (\ [Session]
ls -> ((SessionID -> HotVar Bool -> Session
Session SessionID
sid HotVar Bool
newFlag) Session -> [Session] -> [Session]
forall a. a -> [a] -> [a]
: [Session]
ls, ()))

    let userComp' = do Bool -> Par () -> Par ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg(Par () -> Par ()) -> Par () -> Par ()
forall a b. (a -> b) -> a -> b
$ IO () -> Par ()
forall a. IO a -> Par a
io(IO () -> Par ()) -> IO () -> Par ()
forall a b. (a -> b) -> a -> b
$ do
                           tid2 <- IO ThreadId
myThreadId
                           printf " [%d %s] Starting Par computation on %s.\n" (no sched) (show tid2) name
                       ans <- Par b
userComp
                       -- This add-on to userComp will run only after userComp has completed successfully,
                       -- but that does NOT guarantee that userComp-forked computations have terminated:
                       io$ do when (dbglvl>=1) $ do
                                tid3 <- myThreadId
                                printf " [%d %s] Continuation for %s called, finishing it up (%d)...\n" (no sched) (show tid3) name sid
                              writeIORef ref ans
                              writeHotVarRaw newFlag True
                              modifyHotVar (activeSessions sched) (\ Set SessionID
set -> (SessionID -> Set SessionID -> Set SessionID
forall a. Ord a => a -> Set a -> Set a
S.delete SessionID
sid Set SessionID
set, ()))
        kont :: Word64 -> a -> ROnly ()
        kont SessionID
n = String -> a -> ROnly ()
forall a. String -> a -> ROnly ()
trivialCont(String -> a -> ROnly ()) -> String -> a -> ROnly ()
forall a b. (a -> b) -> a -> b
$ String
"("String -> String -> String
forall a. [a] -> [a] -> [a]
++String
nameString -> String -> String
forall a. [a] -> [a] -> [a]
++String
", sid "String -> String -> String
forall a. [a] -> [a] -> [a]
++SessionID -> String
forall a. Show a => a -> String
show SessionID
sidString -> String -> String
forall a. [a] -> [a] -> [a]
++String
", round "String -> String -> String
forall a. [a] -> [a] -> [a]
++SessionID -> String
forall a. Show a => a -> String
show SessionID
nString -> String -> String
forall a. [a] -> [a] -> [a]
++String
")"
        loop :: Word64 -> ROnly ()
        loop SessionID
n = do flg <- IO Bool -> ReaderT Sched IO Bool
forall a. IO a -> ReaderT Sched IO a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO(IO Bool -> ReaderT Sched IO Bool)
-> IO Bool -> ReaderT Sched IO Bool
forall a b. (a -> b) -> a -> b
$ HotVar Bool -> IO Bool
forall a. HotVar a -> IO a
readIORef HotVar Bool
newFlag
                    unless flg $ do
                      when dbg $ liftIO$ do
                        tid4 <- myThreadId
                        printf " [%d %s] BOUNCE %d... going into reschedule until finished.\n" (no sched) (show tid4) n
                      rescheduleR 0 $ trivialCont$ "("++name++", sid "++show sid++")"
                      loop (n+1)

    -- THIS IS RETURNING TOO EARLY!!:
    runReaderWith sched (C.runContT (unPar userComp') (kont 0))  -- Does this ASSUME child stealing?
    runReaderWith sched (loop 1)

    -- TODO: Ideally we would wait for ALL outstanding (stolen) work on this "team" to complete.

    when (dbglvl>=1)$ do
      active <- readHotVar (activeSessions sched)
      sess@True <- readHotVar newFlag -- ASSERT!
      printf " [%d %s] RETURN from %s (sessFin %s) runContT (%d) active set %s\n"
               (no sched) (show tid) name (show sess) sid (show active)

    -- Here we pop off the frame we added to the session stack:
    modifyHotVar_ (sessions sched) $ \ (Session SessionID
sid2 HotVar Bool
_ : [Session]
tl) ->
        if SessionID
sid SessionID -> SessionID -> Bool
forall a. Eq a => a -> a -> Bool
== SessionID
sid2
        then [Session]
tl
        else String -> [Session]
forall a. HasCallStack => String -> a
error(String -> [Session]) -> String -> [Session]
forall a b. (a -> b) -> a -> b
$ String
"Tried to pop the session stack and found we ("String -> String -> String
forall a. [a] -> [a] -> [a]
++SessionID -> String
forall a. Show a => a -> String
show SessionID
sid
                   String -> String -> String
forall a. [a] -> [a] -> [a]
++String
") were not on the top! (instead "String -> String -> String
forall a. [a] -> [a] -> [a]
++SessionID -> String
forall a. Show a => a -> String
show SessionID
sid2String -> String -> String
forall a. [a] -> [a] -> [a]
++String
")"

    -- By returning here we ARE implicitly reengaging the scheduler, since we
    -- are already inside the rescheduleR loop on this thread
    -- (before runParIO was called in a nested fashion).
    readIORef ref


{-# NOINLINE runParIO #-}
runParIO :: forall a. Par a -> IO a
runParIO Par a
userComp = do
   tid <- IO ThreadId
myThreadId
#if __GLASGOW_HASKELL__ >= 701 /* 20110301 */
    --
    -- We create a thread on each CPU with forkOn.  The CPU on which
    -- the current thread is running will host the main thread; the
    -- other CPUs will host worker threads.
    --
    -- Note: GHC 7.1.20110301 is required for this to work, because that
    -- is when threadCapability was added.
    --
   (main_cpu, _) <- threadCapability tid
#else
    --
    -- Lacking threadCapability, we always pick CPU #0 to run the main
    -- thread.  If the current thread is not running on CPU #0, this
    -- will require some data to be shipped over the memory bus, and
    -- hence will be slightly slower than the version above.
    --
   let main_cpu = 0
#endif
   maybSched <- amINested tid
   tidorig <- myThreadId -- TODO: remove when done debugging
   case maybSched of
     Just (Sched
sched) -> do
       -- Here the current thread is ALREADY a worker.  All we need to
       -- do is plug the users new computation in.

       sid0 <- HotVar SessionID -> IO SessionID
forall a. HotVar a -> IO a
readHotVar (Sched -> HotVar SessionID
sessionCounter Sched
sched)
       when (dbglvl>=1)$ printf " [%d %s] runPar called from existing worker thread, new session (%d)....\n" (no sched) (show tid) (sid0 + 1)
       runNewSessionAndWait "nested runPar" sched userComp

     ------------------------------------------------------------
     -- Non-nested case, make a new set of worker threads:
     ------------------------------------------------------------
     Maybe Sched
Nothing -> do
       allscheds <- Int -> IO [Sched]
makeScheds Int
main_cpu
       [Session _ topSessFlag] <- readHotVar$ sessions$ head allscheds

       mfin <- newEmptyMVar
       doneFlags <- forM (zip [0..] allscheds) $ \(Int
cpu,Sched
sched) -> do
            workerDone <- IO (MVar Int)
forall a. IO (MVar a)
newEmptyMVar
            ----------------------------------------
            let wname = (String
"(worker "String -> String -> String
forall a. [a] -> [a] -> [a]
++Int -> String
forall a. Show a => a -> String
show Int
cpuString -> String -> String
forall a. [a] -> [a] -> [a]
++String
" of originator "String -> String -> String
forall a. [a] -> [a] -> [a]
++ThreadId -> String
forall a. Show a => a -> String
show ThreadId
tidorigString -> String -> String
forall a. [a] -> [a] -> [a]
++String
")")
--            forkOn cpu $ do
            _ <- forkWithExceptions (forkOn cpu) wname $ do
            ------------------------------------------------------------STRT WORKER THREAD
              tid2 <- myThreadId
              registerWorker tid2 sched
              if (cpu /= main_cpu)
                 then do when dbg$ printf " [%d %s] Anonymous worker entering scheduling loop.\n" cpu (show tid2)
                         runReaderWith sched $ rescheduleR 0 (trivialCont (wname++show tid2))
                         when dbg$ printf " [%d] Anonymous worker exited scheduling loop.  FINISHED.\n" cpu
                         putMVar workerDone cpu
                         return ()
                 else do x <- runNewSessionAndWait "top-lvl main worker" sched userComp
                         -- When the main worker finishes we can tell the anonymous "system" workers:
                         writeIORef topSessFlag True
                         when dbg$ do printf " *** Out of entire runContT user computation on main thread %s.\n" (show tid2)
                         --  sanityCheck allscheds
                         putMVar mfin x

              unregisterWorker tid
            ------------------------------------------------------------END WORKER THREAD
            return (if cpu == main_cpu then Nothing else Just workerDone)

       when _WAIT_FOR_WORKERS $ do
           when dbg$ printf " *** [%s] Originator thread: waiting for workers to complete." (show tidorig)
           forM_ (catMaybes doneFlags) $ \ MVar Int
mv -> do
             n <- MVar Int -> IO Int
forall a. MVar a -> IO a
readMVar MVar Int
mv
    --         n <- A.wait mv
             when dbg$ printf "   * [%s]  Worker %s completed\n" (show tidorig) (show n)

       when dbg$ do printf " *** [%s] Reading final MVar on originator thread.\n" (show tidorig)
       -- We don't directly use the thread we come in on.  Rather, that thread waits
       -- waits.  One reason for this is that the main/progenitor thread in
       -- GHC is expensive like a forkOS thread.
       ----------------------------------------
       --              DEBUGGING             --
#ifdef DEBUG_DIRECT
       busyTakeMVar (" The global wait "++ show tidorig) mfin -- Final value.
--       dbgTakeMVar "global waiting thread" mfin -- Final value.
#else
       takeMVar mfin -- Final value.
#endif
       ----------------------------------------

-- Create the default scheduler(s) state:
makeScheds :: Int -> IO [Sched]
makeScheds :: Int -> IO [Sched]
makeScheds Int
main = do
   Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg(IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ do tid <- IO ThreadId
myThreadId
                printf "[initialization] Creating %d worker threads, currently on %s\n" numCapabilities (show tid)
   workpools <- Int -> IO (SimpleDeque (Par ())) -> IO [SimpleDeque (Par ())]
forall (m :: * -> *) a. Applicative m => Int -> m a -> m [a]
replicateM Int
numCapabilities (IO (SimpleDeque (Par ())) -> IO [SimpleDeque (Par ())])
-> IO (SimpleDeque (Par ())) -> IO [SimpleDeque (Par ())]
forall a b. (a -> b) -> a -> b
$ IO (SimpleDeque (Par ()))
forall elt. IO (SimpleDeque elt)
R.newQ
   rngs      <- replicateM numCapabilities $ Random.create >>= newHotVar
   idle      <- newHotVar []
   -- The STACKs are per-worker.. but the root finished flag is shared between all anonymous system workers:
   sessionFinished <- newHotVar False
   sessionStacks   <- mapM newHotVar (replicate numCapabilities [Session baseSessionID sessionFinished])
   activeSessions  <- newHotVar S.empty
   sessionCounter  <- newHotVar (baseSessionID + 1)
   let allscheds = [ Sched { no :: Int
no=Int
x, HotVar [MVar Bool]
idle :: HotVar [MVar Bool]
idle :: HotVar [MVar Bool]
idle, isMain :: Bool
isMain= (Int
xInt -> Int -> Bool
forall a. Eq a => a -> a -> Bool
==Int
main),
                             workpool :: WSDeque (Par ())
workpool=WSDeque (Par ())
SimpleDeque (Par ())
wp, scheds :: [Sched]
scheds=[Sched]
allscheds, rng :: HotVar GenIO
rng=HotVar (Gen RealWorld)
HotVar GenIO
rng,
                             sessions :: HotVar [Session]
sessions = HotVar [Session]
stck,
                             activeSessions :: HotVar (Set SessionID)
activeSessions=HotVar (Set SessionID)
activeSessions,
                             sessionCounter :: HotVar SessionID
sessionCounter=HotVar SessionID
sessionCounter
                           }
                   --  | (x,wp,rng,stck) <- zip4 [0..] workpools rngs sessionStacks
                   | Int
x   <- [Int
0 .. Int
numCapabilitiesInt -> Int -> Int
forall a. Num a => a -> a -> a
-Int
1]
                   | SimpleDeque (Par ())
wp  <- [SimpleDeque (Par ())]
workpools
                   | HotVar (Gen RealWorld)
rng <- [HotVar (Gen RealWorld)]
rngs
                   | HotVar [Session]
stck <- [HotVar [Session]]
sessionStacks
                   ]
   return allscheds


-- The ID of top-level runPar sessions.
baseSessionID :: SessionID
baseSessionID :: SessionID
baseSessionID = SessionID
1000


--------------------------------------------------------------------------------
-- IVar operations
--------------------------------------------------------------------------------

{-# INLINE new  #-}
-- | Creates a new @IVar@
new :: Par (IVar a)
new :: forall a. Par (IVar a)
new  = IO (IVar a) -> Par (IVar a)
forall a. IO a -> Par a
io(IO (IVar a) -> Par (IVar a)) -> IO (IVar a) -> Par (IVar a)
forall a b. (a -> b) -> a -> b
$ do r <- IVarContents a -> IO (IORef (IVarContents a))
forall a. a -> IO (IORef a)
newIORef IVarContents a
forall a. IVarContents a
Empty
              return (IVar r)

{-# INLINE get  #-}
-- | Read the value in an @IVar@.  The 'get' operation can only return when the
-- value has been written by a prior or parallel @put@ to the same
-- @IVar@.
get :: forall a. IVar a -> Par a
get (IVar IORef (IVarContents a)
vr) =  do
  ((a -> Par ()) -> Par a) -> Par a
forall a b. ((a -> Par b) -> Par a) -> Par a
forall (m :: * -> *) a b. MonadCont m => ((a -> m b) -> m a) -> m a
callCC (((a -> Par ()) -> Par a) -> Par a)
-> ((a -> Par ()) -> Par a) -> Par a
forall a b. (a -> b) -> a -> b
$ \a -> Par ()
kont ->
    do
       e  <- IO (IVarContents a) -> Par (IVarContents a)
forall a. IO a -> Par a
io(IO (IVarContents a) -> Par (IVarContents a))
-> IO (IVarContents a) -> Par (IVarContents a)
forall a b. (a -> b) -> a -> b
$ IORef (IVarContents a) -> IO (IVarContents a)
forall a. HotVar a -> IO a
readIORef IORef (IVarContents a)
vr
       case e of
          Full a
a -> a -> Par a
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return a
a
          IVarContents a
_ -> do
            sch <- Par Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
#  ifdef DEBUG_DIRECT
            sn <- io$ makeStableName vr  -- Should probably do the MutVar inside...
            let resched = trace (" ["++ show (no sch) ++ "]  - Rescheduling on unavailable ivar "++show (hashStableName sn)++"!")
#else
            let resched =
#  endif
                          Par a
forall a. Par a
longjmpSched -- Invariant: kont must not be lost.
            -- Because we continue on the same processor the Sched stays the same:
            -- TODO: Try NOT using monadic values as first class.  Check for performance effect:
            r <- io$ atomicModifyIORef vr $ \IVarContents a
x -> case IVarContents a
x of
                      IVarContents a
Empty      -> ([a -> IO ()] -> IVarContents a
forall a. [a -> IO ()] -> IVarContents a
Blocked [Sched -> Par () -> IO ()
pushWork Sched
sch (Par () -> IO ()) -> (a -> Par ()) -> a -> IO ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> Par ()
kont], Par a
forall a. Par a
resched)
                      Full a
a     -> (a -> IVarContents a
forall a. a -> IVarContents a
Full a
a, a -> Par a
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return a
a) -- kont is implicit here.
                      Blocked [a -> IO ()]
ks -> ([a -> IO ()] -> IVarContents a
forall a. [a -> IO ()] -> IVarContents a
Blocked (Sched -> Par () -> IO ()
pushWork Sched
sch (Par () -> IO ()) -> (a -> Par ()) -> a -> IO ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> Par ()
kont(a -> IO ()) -> [a -> IO ()] -> [a -> IO ()]
forall a. a -> [a] -> [a]
:[a -> IO ()]
ks), Par a
forall a. Par a
resched)
            r

-- | NOTE unsafePeek is NOT exposed directly through this module.  (So
-- this module remains SAFE in the Safe Haskell sense.)  It can only
-- be accessed by importing Control.Monad.Par.Unsafe.
{-# INLINE unsafePeek #-}
unsafePeek :: IVar a -> Par (Maybe a)
unsafePeek :: forall a. IVar a -> Par (Maybe a)
unsafePeek (IVar IORef (IVarContents a)
v) = do
  e  <- IO (IVarContents a) -> Par (IVarContents a)
forall a. IO a -> Par a
io(IO (IVarContents a) -> Par (IVarContents a))
-> IO (IVarContents a) -> Par (IVarContents a)
forall a b. (a -> b) -> a -> b
$ IORef (IVarContents a) -> IO (IVarContents a)
forall a. HotVar a -> IO a
readIORef IORef (IVarContents a)
v
  case e of
    Full a
a -> Maybe a -> Par (Maybe a)
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return (a -> Maybe a
forall a. a -> Maybe a
Just a
a)
    IVarContents a
_      -> Maybe a -> Par (Maybe a)
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe a
forall a. Maybe a
Nothing

------------------------------------------------------------
{-# INLINE put_ #-}
-- | @put_@ is a version of @put@ that is head-strict rather than fully-strict.
--   In this scheduler, puts immediately execute woken work in the current thread.
put_ :: forall a. IVar a -> a -> Par ()
put_ (IVar IORef (IVarContents a)
vr) !a
content = do
   sched <- Par Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
   ks <- io$ do
      ks <- atomicModifyIORef vr $ \IVarContents a
e -> case IVarContents a
e of
               IVarContents a
Empty      -> (a -> IVarContents a
forall a. a -> IVarContents a
Full a
content, [])
               Full a
_     -> String -> (IVarContents a, [a -> IO ()])
forall a. HasCallStack => String -> a
error String
"multiple put"
               Blocked [a -> IO ()]
ks -> (a -> IVarContents a
forall a. a -> IVarContents a
Full a
content, [a -> IO ()]
ks)
#ifdef DEBUG_DIRECT
      when (dbglvl >=  3) $ do
         sn <- makeStableName vr
         printf " [%d] Put value %s into IVar %d.  Waking up %d continuations.\n"
                (no sched) (show content) (hashStableName sn) (length ks)
         return ()
#endif
      return ks
   wakeUp sched ks content

-- | NOTE unsafeTryPut is NOT exposed directly through this module.  (So
-- this module remains SAFE in the Safe Haskell sense.)  It can only
-- be accessed by importing Control.Monad.Par.Unsafe.
{-# INLINE unsafeTryPut #-}
unsafeTryPut :: forall b. IVar b -> b -> Par b
unsafeTryPut (IVar IORef (IVarContents b)
vr) !b
content = do
   -- Head strict rather than fully strict.
   sched <- Par Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
   (ks,res) <- io$ do
      pr <- atomicModifyIORef vr $ \IVarContents b
e -> case IVarContents b
e of
                   IVarContents b
Empty      -> (b -> IVarContents b
forall a. a -> IVarContents a
Full b
content, ([], b
content))
                   Full b
x     -> (b -> IVarContents b
forall a. a -> IVarContents a
Full b
x, ([], b
x))
                   Blocked [b -> IO ()]
ks -> (b -> IVarContents b
forall a. a -> IVarContents a
Full b
content, ([b -> IO ()]
ks, b
content))
#ifdef DEBUG_DIRECT
      sn <- makeStableName vr
      printf " [%d] unsafeTryPut: value %s in IVar %d.  Waking up %d continuations.\n"
             (no sched) (show content) (hashStableName sn) (length (fst pr))
#endif
      return pr
   wakeUp sched ks content
   return res

-- | When an IVar is filled in, continuations wake up.
{-# INLINE wakeUp #-}
wakeUp :: Sched -> [a -> IO ()]-> a -> Par ()
wakeUp :: forall a. Sched -> [a -> IO ()] -> a -> Par ()
wakeUp Sched
_sched [a -> IO ()]
ks a
arg = [a -> IO ()] -> Par ()
loop [a -> IO ()]
ks
 where
   loop :: [a -> IO ()] -> Par ()
loop [] = () -> Par ()
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
   loop (a -> IO ()
kont:[a -> IO ()]
rest) = do
     -- FIXME -- without strict firewalls keeping ivars from moving
     -- between runPar sessions, if we allow nested scheduler use
     -- we could potentially wake up work belonging to a different
     -- runPar and thus bring it into our worker and delay our own
     -- continuation until its completion.
     if Bool
_PARPUTS then
       -- We do NOT force the putting thread to postpone its continuation.
       do _ <- Par () -> Par (IVar ())
forall a. Par a -> Par (IVar a)
spawn_(Par () -> Par (IVar ())) -> Par () -> Par (IVar ())
forall a b. (a -> b) -> a -> b
$ (a -> IO ()) -> [a -> IO ()] -> Par ()
pMap a -> IO ()
kont [a -> IO ()]
rest
          return ()
       -- case rest of
       --   [] -> spawn_$ io$ kont arg
       --   _  -> spawn_$ do spawn_$ io$ kont arg
       --                    io$ parchain rest
       -- error$"FINISHME - wake "++show (length ks)++" conts"
      else
       -- This version sacrifices a parallelism opportunity and
       -- imposes additional serialization.
       --
       -- [2012.08.31] WARNING -- this serialzation CAN cause deadlock.
       -- This "optimization" should not be on the table.
       -- mapM_ ($arg) ks
       do IO () -> Par ()
forall a. IO a -> Par a
io(IO () -> Par ()) -> IO () -> Par ()
forall a b. (a -> b) -> a -> b
$ a -> IO ()
kont a
arg
          [a -> IO ()] -> Par ()
loop [a -> IO ()]
rest
     () -> Par ()
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

   pMap :: (a -> IO ()) -> [a -> IO ()] -> Par ()
pMap a -> IO ()
kont [] = IO () -> Par ()
forall a. IO a -> Par a
io(IO () -> Par ()) -> IO () -> Par ()
forall a b. (a -> b) -> a -> b
$ a -> IO ()
kont a
arg
   pMap a -> IO ()
kont (a -> IO ()
more:[a -> IO ()]
rest) =
     do _ <- Par () -> Par (IVar ())
forall a. Par a -> Par (IVar a)
spawn_(Par () -> Par (IVar ())) -> Par () -> Par (IVar ())
forall a b. (a -> b) -> a -> b
$ IO () -> Par ()
forall a. IO a -> Par a
io(IO () -> Par ()) -> IO () -> Par ()
forall a b. (a -> b) -> a -> b
$ a -> IO ()
kont a
arg
        pMap more rest

   -- parchain [kont] = kont arg
   -- parchain (kont:rest) = do spawn$ io$ kont arg
   --                           parchain rest


------------------------------------------------------------
{-# INLINE fork #-}
fork :: Par () -> Par ()
fork :: Par () -> Par ()
fork Par ()
task =
  -- Forking the "parent" means offering up the continuation of the
  -- fork rather than the task argument for stealing:
  case Bool
_FORKPARENT of
    Bool
True -> do
      sched <- Par Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
      callCC$ \() -> Par ()
parent -> do
         let wrapped :: Par ()
wrapped = () -> Par ()
parent ()
         IO () -> Par ()
forall a. IO a -> Par a
io(IO () -> Par ()) -> IO () -> Par ()
forall a b. (a -> b) -> a -> b
$ Sched -> Par () -> IO ()
pushWork Sched
sched Par ()
wrapped
         -- Then execute the child task and return to the scheduler when it is complete:
         Par ()
task
         -- If we get to this point we have finished the child task:
         _ <- Par (ZonkAny 3)
forall a. Par a
longjmpSched -- We reschedule to pop the cont we pushed.
         -- TODO... OPTIMIZATION: we could also try the pop directly, and if it succeeds return normally....
         io$ printf " !!! ERROR: Should never reach this point #1\n"

      when dbg$ do
       sched2 <- RD.ask
       io$ printf "  -  called parent continuation... was on worker [%d] now on worker [%d]\n" (no sched) (no sched2)
       return ()

    Bool
False -> do
      sch <- Par Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
      when dbg$ io$ printf " [%d] forking task...\n" (no sch)
      io$ pushWork sch task

-- This routine "longjmp"s to the scheduler, throwing out its own continuation.
longjmpSched :: Par a
-- longjmpSched = Par $ C.ContT rescheduleR
longjmpSched :: forall a. Par a
longjmpSched = ContT () (ReaderT Sched IO) a -> Par a
forall a. ContT () (ReaderT Sched IO) a -> Par a
Par (ContT () (ReaderT Sched IO) a -> Par a)
-> ContT () (ReaderT Sched IO) a -> Par a
forall a b. (a -> b) -> a -> b
$ ((a -> ROnly ()) -> ROnly ()) -> ContT () (ReaderT Sched IO) a
forall {k} (r :: k) (m :: k -> *) a.
((a -> m r) -> m r) -> ContT r m a
C.ContT (\ a -> ROnly ()
_k -> SessionID -> (ZonkAny 2 -> ROnly ()) -> ROnly ()
forall a. SessionID -> (a -> ROnly ()) -> ROnly ()
rescheduleR SessionID
0 (String -> ZonkAny 2 -> ROnly ()
forall a. String -> a -> ROnly ()
trivialCont String
"longjmpSched"))

-- Reschedule the scheduler loop until it observes sessionFinished==True, and
-- then it finally invokes its continuation.
rescheduleR :: Word64 -> (a -> ROnly ()) -> ROnly ()
rescheduleR :: forall a. SessionID -> (a -> ROnly ()) -> ROnly ()
rescheduleR SessionID
cnt a -> ROnly ()
kont = do
  mysched <- ReaderT Sched IO Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
  when dbg$ liftIO$ do tid <- myThreadId
                       sess <- readSessions mysched
                       null <- R.nullQ (workpool mysched)
                       printf " [%d %s]  - Reschedule #%d... sessions %s, pool empty %s\n"
                              (no mysched) (show tid) cnt (show sess) (show null)
  mtask  <- liftIO$ popWork mysched
  case mtask of
    Maybe (Par ())
Nothing -> do
                  (Session _ finRef):_ <- IO [Session] -> ReaderT Sched IO [Session]
forall a. IO a -> ReaderT Sched IO a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO(IO [Session] -> ReaderT Sched IO [Session])
-> IO [Session] -> ReaderT Sched IO [Session]
forall a b. (a -> b) -> a -> b
$ HotVar [Session] -> IO [Session]
forall a. HotVar a -> IO a
readIORef (HotVar [Session] -> IO [Session])
-> HotVar [Session] -> IO [Session]
forall a b. (a -> b) -> a -> b
$ Sched -> HotVar [Session]
sessions Sched
mysched
                  fin <- liftIO$ readIORef finRef
                  if fin
                   then do when (dbglvl >= 1) $ liftIO $ do
                             tid <- myThreadId
                             sess <- readSessions mysched
                             printf " [%d %s]  - DROP out of reschedule loop, sessionFinished=%s, all sessions %s\n"
                                    (no mysched) (show tid) (show fin) (show sess)
                             empt <- R.nullQ$ workpool mysched
                             when (not empt) $ do
                               printf " [%d %s] - WARNING - leaving rescheduleR while local workpoll is nonempty\n"
                                      (no mysched) (show tid)

                           kont (error "Direct.hs: The result value from rescheduleR should not be used.")
                   else do
                     -- when (dbglvl >= 1) $ liftIO $ do
                     --     tid <- myThreadId
                     --     sess <- readSessions mysched
                     --     printf " [%d %s]  -    Apparently NOT finished with head session... trying to steal, all sessions %s\n"
                     --            (no mysched) (show tid) (show sess)
                     liftIO$ steal mysched
#ifdef WAKEIDLE
--                     io$ tryWakeIdle (idle mysched)
#endif
                     liftIO yield
                     rescheduleR (cnt+1) kont
    Just Par ()
task -> do
       -- When popping work from our own queue the Sched (Reader value) stays the same:
       Bool -> ROnly () -> ROnly ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg (ROnly () -> ROnly ()) -> ROnly () -> ROnly ()
forall a b. (a -> b) -> a -> b
$ do sn <- IO (StableName (Par ())) -> ReaderT Sched IO (StableName (Par ()))
forall a. IO a -> ReaderT Sched IO a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO(IO (StableName (Par ()))
 -> ReaderT Sched IO (StableName (Par ())))
-> IO (StableName (Par ()))
-> ReaderT Sched IO (StableName (Par ()))
forall a b. (a -> b) -> a -> b
$ Par () -> IO (StableName (Par ()))
forall a. a -> IO (StableName a)
makeStableName Par ()
task
                     liftIO$ printf " [%d] popped work %d from own queue\n" (no mysched) (hashStableName sn)
       let C.ContT (() -> ROnly ()) -> ROnly ()
fn = Par () -> ContT () (ReaderT Sched IO) ()
forall a. Par a -> ContT () (ReaderT Sched IO) a
unPar Par ()
task
       -- Run the stolen task with a continuation that returns to the scheduler if the task exits normally:
       (() -> ROnly ()) -> ROnly ()
fn (\ ()
_ -> do
           sch <- ReaderT Sched IO Sched
forall r (m :: * -> *). MonadReader r m => m r
RD.ask
           when dbg$ liftIO$ printf "  + task finished successfully on cpu %d, calling reschedule continuation..\n" (no sch)
           rescheduleR 0 kont)


-- | Attempt to steal work or, failing that, give up and go idle.
--
--   The current policy is to do a burst of of N tries without
--   yielding or pausing in between.
steal :: Sched -> IO ()
steal :: Sched -> IO ()
steal mysched :: Sched
mysched@Sched{ HotVar [MVar Bool]
idle :: Sched -> HotVar [MVar Bool]
idle :: HotVar [MVar Bool]
idle, [Sched]
scheds :: Sched -> [Sched]
scheds :: [Sched]
scheds, HotVar GenIO
rng :: Sched -> HotVar GenIO
rng :: HotVar GenIO
rng, no :: Sched -> Int
no=Int
my_no } = do
  Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Int
dbglvlInt -> Int -> Bool
forall a. Ord a => a -> a -> Bool
>=Int
2)(IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ do tid <- IO ThreadId
myThreadId
                       printf " [%d %s]  + stealing\n" my_no (show tid)
  i <- Int -> IO Int
getnext (-Int
1 :: Int)
  go maxtries i
 where
--    maxtries = numCapabilities -- How many times should we attempt theft before going idle?
    maxtries :: Int
maxtries = Int
20 Int -> Int -> Int
forall a. Num a => a -> a -> a
* Int
numCapabilities -- How many times should we attempt theft before going idle?

    getnext :: Int -> IO Int
getnext Int
_ = HotVar GenIO -> IO Int
rand HotVar GenIO
rng

    ----------------------------------------
    -- IDLING behavior:
    go :: Int -> Int -> IO ()
go Int
0 Int
_ | Bool
_IDLING_ON =
            do m <- IO (MVar Bool)
forall a. IO (MVar a)
newEmptyMVar
               r <- modifyHotVar idle $ \[MVar Bool]
is -> (MVar Bool
mMVar Bool -> [MVar Bool] -> [MVar Bool]
forall a. a -> [a] -> [a]
:[MVar Bool]
is, [MVar Bool]
is)
               if length r == numCapabilities - 1
                  then do
                     when dbg$ printf " [%d]  | waking up all threads\n" my_no
                     writeHotVarRaw idle []
                     mapM_ (\MVar Bool
vr -> MVar Bool -> Bool -> IO ()
forall a. MVar a -> a -> IO ()
putMVar MVar Bool
vr Bool
True) r
                  else do
                    (Session _ finRef):_ <- readIORef $ sessions mysched
                    fin <- readIORef finRef
                    done <- if fin then pure True else takeMVar m
                    if done
                       then do
                         when dbg$ printf " [%d]  | shutting down\n" my_no
                         return ()
                       else do
                         when dbg$ printf " [%d]  | woken up\n" my_no
                         i <- getnext (-1::Int)
                         go maxtries i

    -- We need to return from this loop to check sessionFinished and exit the scheduler if necessary.
    go Int
0 Int
_i | Bool
_IDLING_ON Bool -> Bool -> Bool
forall a. Eq a => a -> a -> Bool
== Bool
False = IO ()
yield

    ----------------------------------------
    go Int
tries Int
i
      | Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
my_no = do i' <- Int -> IO Int
getnext Int
i
                        go (tries-1) i'

      | Bool
otherwise     = do
         -- We ONLY go through the global sched array to access victims:
         let schd :: Sched
schd = [Sched]
scheds[Sched] -> Int -> Sched
forall a. HasCallStack => [a] -> Int -> a
!!Int
i
         Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Int
dbglvlInt -> Int -> Bool
forall a. Ord a => a -> a -> Bool
>=Int
2)(IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ String -> Int -> Int -> IO ()
forall r. PrintfType r => String -> r
printf String
" [%d]  | trying steal from %d\n" Int
my_no (Sched -> Int
no Sched
schd)

--         let dq = workpool schd :: WSDeque (Par ())
         let dq :: WSDeque (Par ())
dq = Sched -> WSDeque (Par ())
workpool Sched
schd
         r <- SimpleDeque (Par ()) -> IO (Maybe (Par ()))
forall a. SimpleDeque a -> IO (Maybe a)
R.tryPopR WSDeque (Par ())
SimpleDeque (Par ())
dq

         case r of
           Just Par ()
task  -> do
              Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg(IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ do sn <- Par () -> IO (StableName (Par ()))
forall a. a -> IO (StableName a)
makeStableName Par ()
task
                           printf " [%d]  | stole work (unit %d) from cpu %d\n" my_no (hashStableName sn) (no schd)
              Sched -> ROnly () -> IO ()
forall r (m :: * -> *) a. r -> ReaderT r m a -> m a
runReaderWith Sched
mysched (ROnly () -> IO ()) -> ROnly () -> IO ()
forall a b. (a -> b) -> a -> b
$
                ContT () (ReaderT Sched IO) () -> (() -> ROnly ()) -> ROnly ()
forall {k} (r :: k) (m :: k -> *) a.
ContT r m a -> (a -> m r) -> m r
C.runContT (Par () -> ContT () (ReaderT Sched IO) ()
forall a. Par a -> ContT () (ReaderT Sched IO) a
unPar Par ()
task)
                 (\()
_ -> do
                   Bool -> ROnly () -> ROnly ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
dbg(ROnly () -> ROnly ()) -> ROnly () -> ROnly ()
forall a b. (a -> b) -> a -> b
$ do sn <- IO (StableName (Par ())) -> ReaderT Sched IO (StableName (Par ()))
forall a. IO a -> ReaderT Sched IO a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO(IO (StableName (Par ()))
 -> ReaderT Sched IO (StableName (Par ())))
-> IO (StableName (Par ()))
-> ReaderT Sched IO (StableName (Par ()))
forall a b. (a -> b) -> a -> b
$ Par () -> IO (StableName (Par ()))
forall a. a -> IO (StableName a)
makeStableName Par ()
task
                                liftIO$ printf " [%d]  | DONE running stolen work (unit %d) from %d\n" my_no (hashStableName sn) (no schd)
                   () -> ROnly ()
forall a. a -> ReaderT Sched IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ())

           Maybe (Par ())
Nothing -> do i' <- Int -> IO Int
getnext Int
i
                         go (tries-1) i'

-- | The continuation which should not be called.
_errK :: t
_errK :: forall t. t
_errK = String -> t
forall a. HasCallStack => String -> a
error String
"Error cont: this closure shouldn't be used"

trivialCont :: String -> a -> ROnly ()
#ifdef DEBUG_DIRECT
trivialCont str _ = do
--                trace (str ++" trivialCont evaluated!")
                liftIO$ printf " !! trivialCont evaluated, msg: %s\n" str
#else
trivialCont :: forall a. String -> a -> ROnly ()
trivialCont String
_str a
_ = do
#endif
                () -> ROnly ()
forall a. a -> ReaderT Sched IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

----------------------------------------------------------------------------------------------------


--------------------------------------------------------------------------------
-- <boilerplate>

-- TEMP: TODO: Factor out this boilerplate somehow.

{-# INLINE spawn1_ #-}
-- Spawn a one argument function instead of a thunk.  This is good for debugging if the value supports "Show".
spawn1_ :: forall a b. (a -> Par b) -> a -> Par (IVar b)
spawn1_ a -> Par b
f a
x =
#ifdef DEBUG_DIRECT
 do sn  <- io$ makeStableName f
    sch <- RD.ask; when dbg$ io$ printf " [%d] spawning fn %d with arg %s\n" (no sch) (hashStableName sn) (show x)
#endif
    Par b -> Par (IVar b)
forall a. Par a -> Par (IVar a)
spawn_ (a -> Par b
f a
x)

-- The following is usually inefficient!
newFull_ :: forall a. a -> Par (IVar a)
newFull_ a
a = do v <- Par (IVar a)
forall a. Par (IVar a)
new
                put_ v a
                return v

newFull :: forall a. NFData a => a -> Par (IVar a)
newFull a
a = a -> Par (IVar a) -> Par (IVar a)
forall a b. NFData a => a -> b -> b
deepseq a
a (a -> Par (IVar a)
forall a. a -> Par (IVar a)
newFull_ a
a)

{-# INLINE put  #-}
put :: forall a. NFData a => IVar a -> a -> Par ()
put IVar a
v a
a = a -> Par () -> Par ()
forall a b. NFData a => a -> b -> b
deepseq a
a (IVar a -> a -> Par ()
forall a. IVar a -> a -> Par ()
put_ IVar a
v a
a)

spawn :: forall a. NFData a => Par a -> Par (IVar a)
spawn Par a
p  = do r <- Par (IVar a)
forall a. Par (IVar a)
new;  fork (p >>= put r);   return r
spawn_ :: forall a. Par a -> Par (IVar a)
spawn_ Par a
p = do r <- Par (IVar a)
forall a. Par (IVar a)
new;  fork (p >>= put_ r);  return r
spawnP :: forall a. NFData a => a -> Par (IVar a)
spawnP a
a = Par a -> Par (IVar a)
forall a. NFData a => Par a -> Par (IVar a)
spawn (a -> Par a
forall a. a -> Par a
forall (m :: * -> *) a. Monad m => a -> m a
return a
a)

-- In Debug mode we require that IVar contents be Show-able:
#ifdef DEBUG_DIRECT
put    :: (Show a, NFData a) => IVar a -> a -> Par ()
spawn  :: (Show a, NFData a) => Par a -> Par (IVar a)
spawn_ :: Show a => Par a -> Par (IVar a)
spawn1_ :: (Show a, Show b) => (a -> Par b) -> a -> Par (IVar b)
spawnP :: (Show a, NFData a) => a -> Par (IVar a)
put_   :: Show a => IVar a -> a -> Par ()
get    :: Show a => IVar a -> Par a
runPar :: Show a => Par a -> a
runParIO :: Show a => Par a -> IO a
newFull :: (Show a, NFData a) => a -> Par (IVar a)
newFull_ ::  Show a => a -> Par (IVar a)
unsafeTryPut :: Show b => IVar b -> b -> Par b
#else
spawn  :: NFData a => Par a -> Par (IVar a)
spawn_ :: Par a -> Par (IVar a)
spawn1_ :: (a -> Par b) -> a -> Par (IVar b)
spawnP :: NFData a => a -> Par (IVar a)
put_   :: IVar a -> a -> Par ()
put    :: NFData a => IVar a -> a -> Par ()
get    :: IVar a -> Par a
runPar :: Par a -> a
runParIO :: Par a -> IO a
newFull :: NFData a => a -> Par (IVar a)
newFull_ ::  a -> Par (IVar a)
unsafeTryPut :: IVar b -> b -> Par b

-- We can't make proper instances with the extra Show constraints:
instance PC.ParFuture IVar Par  where
  get :: forall a. IVar a -> Par a
get    = IVar a -> Par a
forall a. IVar a -> Par a
get
  spawn :: forall a. NFData a => Par a -> Par (IVar a)
spawn  = Par a -> Par (IVar a)
forall a. NFData a => Par a -> Par (IVar a)
spawn
  spawn_ :: forall a. Par a -> Par (IVar a)
spawn_ = Par a -> Par (IVar a)
forall a. Par a -> Par (IVar a)
spawn_
  spawnP :: forall a. NFData a => a -> Par (IVar a)
spawnP = a -> Par (IVar a)
forall a. NFData a => a -> Par (IVar a)
spawnP

instance PC.ParIVar IVar Par  where
  fork :: Par () -> Par ()
fork = Par () -> Par ()
fork
  new :: forall a. Par (IVar a)
new  = Par (IVar a)
forall a. Par (IVar a)
new
  put_ :: forall a. IVar a -> a -> Par ()
put_ = IVar a -> a -> Par ()
forall a. IVar a -> a -> Par ()
put_
  newFull :: forall a. NFData a => a -> Par (IVar a)
newFull = a -> Par (IVar a)
forall a. NFData a => a -> Par (IVar a)
newFull
  newFull_ :: forall a. a -> Par (IVar a)
newFull_ = a -> Par (IVar a)
forall a. a -> Par (IVar a)
newFull_

instance UN.ParUnsafe IVar Par  where
  unsafePeek :: forall a. IVar a -> Par (Maybe a)
unsafePeek   = IVar a -> Par (Maybe a)
forall a. IVar a -> Par (Maybe a)
unsafePeek
  unsafeTryPut :: forall b. IVar b -> b -> Par b
unsafeTryPut = IVar a -> a -> Par a
forall b. IVar b -> b -> Par b
unsafeTryPut
  unsafeParIO :: forall a. IO a -> Par a
unsafeParIO  = IO a -> Par a
forall a. IO a -> Par a
unsafeParIO
#endif



#ifdef NEW_GENERIC
instance PU.ParMonad Par where
  fork = fork
  internalLiftIO io = Par (lift $ lift io)

instance PU.ParThreadSafe Par where
  unsafeParIO io = Par (lift $ lift io)

instance PN.ParFuture Par where
  type Future Par = IVar
  type FutContents Par a = ()
  get    = get
  spawn  = spawn
  spawn_ = spawn_
  spawnP = spawnP

instance PN.ParIVar Par  where
  new  = new
  put_ = put_
  newFull = newFull
  newFull_ = newFull_
#endif

-- </boilerplate>
--------------------------------------------------------------------------------


{-# INLINE runReaderWith #-}
-- | Arguments flipped for convenience.
runReaderWith :: r -> RD.ReaderT r m a -> m a
runReaderWith :: forall r (m :: * -> *) a. r -> ReaderT r m a -> m a
runReaderWith r
state ReaderT r m a
m = ReaderT r m a -> r -> m a
forall r (m :: * -> *) a. ReaderT r m a -> r -> m a
RD.runReaderT ReaderT r m a
m r
state


--------------------------------------------------------------------------------
-- DEBUGGING TOOLs
--------------------------------------------------------------------------------

-- Make sure there is no work left in any deque after exiting.
_sanityCheck :: [Sched] -> IO ()
_sanityCheck :: [Sched] -> IO ()
_sanityCheck [Sched]
allscheds = do
  [Sched] -> (Sched -> IO ()) -> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [Sched]
allscheds ((Sched -> IO ()) -> IO ()) -> (Sched -> IO ()) -> IO ()
forall a b. (a -> b) -> a -> b
$ \ Sched{Int
no :: Sched -> Int
no :: Int
no, WSDeque (Par ())
workpool :: Sched -> WSDeque (Par ())
workpool :: WSDeque (Par ())
workpool} -> do
     b <- SimpleDeque (Par ()) -> IO Bool
forall elt. SimpleDeque elt -> IO Bool
R.nullQ WSDeque (Par ())
SimpleDeque (Par ())
workpool
     when (not b) $ do
         () <- printf "WARNING: After main thread exited non-empty queue remains for worker %d\n" no
         return ()
  String -> IO ()
forall r. PrintfType r => String -> r
printf String
"Sanity check complete.\n"


-- | This tries to localize the blocked-indefinitely exception:
_dbgTakeMVar :: String -> MVar a -> IO a
_dbgTakeMVar :: forall a. String -> MVar a -> IO a
_dbgTakeMVar String
msg MVar a
mv =
--  catch (takeMVar mv) ((\_ -> doDebugStuff) :: BlockedIndefinitelyOnMVar -> IO a)
  IO a -> (IOError -> IO a) -> IO a
forall e a. Exception e => IO a -> (e -> IO a) -> IO a
E.catch (MVar a -> IO a
forall a. MVar a -> IO a
takeMVar MVar a
mv) (\(IOError
_::IOError) -> IO a
doDebugStuff)
 where
   doDebugStuff :: IO a
doDebugStuff = do String -> String -> IO ()
forall r. PrintfType r => String -> r
printf String
"This takeMVar blocked indefinitely!: %s\n" String
msg
                     String -> IO a
forall a. HasCallStack => String -> a
error String
"failed"

-- | For debugging purposes.  This can help us figure out (by an ugly
--   process of elimination) which MVar reads are leading to a "Thread
--   blocked indefinitely" exception.
{-
busyTakeMVar :: String -> MVar a -> IO a
busyTakeMVar msg mv = try (10 * 1000 * 1000)
 where
 try 0 = do
   when dbg $ do
     tid <- myThreadId
     -- After we've failed enough times, start complaining:
     printf "%s not getting anywhere, msg: %s\n" (show tid) msg
   try (100 * 1000)
 try n = do
   x <- tryTakeMVar mv
   case x of
     Just y  -> return y
     Nothing -> do yield; try (n-1)
-}

-- | Fork a thread but ALSO set up an error handler that suppresses
--   MVar exceptions.
_forkIO_Suppress :: Int -> IO () -> IO ThreadId
_forkIO_Suppress :: Int -> IO () -> IO ThreadId
_forkIO_Suppress Int
whre IO ()
action =
  Int -> IO () -> IO ThreadId
forkOn Int
whre (IO () -> IO ThreadId) -> IO () -> IO ThreadId
forall a b. (a -> b) -> a -> b
$
           (BlockedIndefinitelyOnMVar -> IO ()) -> IO () -> IO ()
forall e a. Exception e => (e -> IO a) -> IO a -> IO a
E.handle (\BlockedIndefinitelyOnMVar
e ->
                      case (BlockedIndefinitelyOnMVar
e :: E.BlockedIndefinitelyOnMVar) of
                       BlockedIndefinitelyOnMVar
_ -> do
                               String -> IO ()
putStrLn(String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$String
"CAUGHT child thread exception: "String -> String -> String
forall a. [a] -> [a] -> [a]
++BlockedIndefinitelyOnMVar -> String
forall a. Show a => a -> String
show BlockedIndefinitelyOnMVar
e
                               () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
                    )
           IO ()
action


-- | Exceptions that walk up the fork tree of threads:
forkWithExceptions :: (IO () -> IO ThreadId) -> String -> IO () -> IO ThreadId
forkWithExceptions :: (IO () -> IO ThreadId) -> String -> IO () -> IO ThreadId
forkWithExceptions IO () -> IO ThreadId
forkit String
descr IO ()
action = do
   parent <- IO ThreadId
myThreadId
   forkit $ do
      tid <- myThreadId
      E.catch action
         (\ SomeException
e ->
           case SomeException -> Maybe AsyncException
forall e. Exception e => SomeException -> Maybe e
E.fromException SomeException
e of
             Just AsyncException
E.ThreadKilled -> String -> String -> String -> IO ()
forall r. PrintfType r => String -> r
printf
                                    String
"\nThreadKilled exception inside child thread, %s (not propagating!): %s\n" (ThreadId -> String
forall a. Show a => a -> String
show ThreadId
tid) (String -> String
forall a. Show a => a -> String
show String
descr)
             Maybe AsyncException
_  -> do String -> String -> String -> String -> IO ()
forall r. PrintfType r => String -> r
printf
                        String
"\nException inside child thread %s, %s: %s\n" (String -> String
forall a. Show a => a -> String
show String
descr) (ThreadId -> String
forall a. Show a => a -> String
show ThreadId
tid) (SomeException -> String
forall a. Show a => a -> String
show SomeException
e)
                      ThreadId -> SomeException -> IO ()
forall e. Exception e => ThreadId -> e -> IO ()
E.throwTo ThreadId
parent (SomeException
e :: E.SomeException)
         )


-- Do all the memory reads to snapshot the current session stack:
readSessions :: Sched -> IO [(SessionID, Bool)]
readSessions :: Sched -> IO [(SessionID, Bool)]
readSessions Sched
sched = do
  ls <- HotVar [Session] -> IO [Session]
forall a. HotVar a -> IO a
readIORef (Sched -> HotVar [Session]
sessions Sched
sched)
  bools <- mapM (\ (Session SessionID
_ HotVar Bool
r) -> HotVar Bool -> IO Bool
forall a. HotVar a -> IO a
readIORef HotVar Bool
r) ls
  return (zip (map (\ (Session SessionID
sid HotVar Bool
_) -> SessionID
sid) ls) bools)