[project @ 2003-09-21 22:20:51 by wolfgang]

Bound Threads
=============

Introduce a way to use foreign libraries that rely on thread local state
from multiple threads (mainly affects the threaded RTS).

See the file threads.tex in CVS at haskell-report/ffi/threads.tex
(not entirely finished yet) for a definition of this extension. A less formal
description is also found in the documentation of Control.Concurrent.

The changes mostly affect the THREADED_RTS (./configure --enable-threaded-rts),
except for saving & restoring errno on a per-TSO basis, which is also necessary
for the non-threaded RTS (a bugfix).

Detailed list of changes
------------------------

- errno is saved in the TSO object and restored when necessary:
ghc/includes/TSO.h, ghc/rts/Interpreter.c, ghc/rts/Schedule.c

- rts_mainLazyIO is no longer needed, main is no special case anymore
ghc/includes/RtsAPI.h, ghc/rts/RtsAPI.c, ghc/rts/Main.c, ghc/rts/Weak.c

- passCapability: a new function that releases the capability and "passes"
  it to a specific OS thread:
ghc/rts/Capability.h ghc/rts/Capability.c

- waitThread(), scheduleWaitThread() and schedule() get an optional
  Capability *initialCapability passed as an argument:
ghc/includes/SchedAPI.h, ghc/rts/Schedule.c, ghc/rts/RtsAPI.c

- Bound Thread scheduling (that's what this is all about):
ghc/rts/Schedule.h, ghc/rts/Schedule.c

- new Primop isCurrentThreadBound#:
ghc/compiler/prelude/primops.txt.pp, ghc/includes/PrimOps.h, ghc/rts/PrimOps.hc,
ghc/rts/Schedule.h, ghc/rts/Schedule.c

- a simple function, rtsSupportsBoundThreads, that returns true if THREADED_RTS
  is defined:
ghc/rts/Schedule.h, ghc/rts/Schedule.c

- a new implementation of forkProcess (the old implementation stays in place
  for the non-threaded case). Partially broken; works for the standard
  fork-and-exec case, but not for much else. A proper forkProcess is
  really next to impossible to implement:
ghc/rts/Schedule.c

- Library support for bound threads:
    Control.Concurrent.
      rtsSupportsBoundThreads, isCurrentThreadBound, forkOS,
      runInBoundThread, runInUnboundThread
libraries/base/Control/Concurrent.hs, libraries/base/Makefile,
libraries/base/include/HsBase.h, libraries/base/cbits/forkOS.c (new file)

1 files changed, 5 insertions, 3 deletions

diff --git a/ghc/includes/SchedAPI.h b/ghc/includes/SchedAPI.h
index 524b1da9f5..b0cee60f04 100644
--- a/ghc/includes/SchedAPI.h
+++ b/ghc/includes/SchedAPI.h
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: SchedAPI.h,v 1.17 2002/12/27 12:33:21 panne Exp $
+ * $Id: SchedAPI.h,v 1.18 2003/09/21 22:20:53 wolfgang Exp $
  *
  * (c) The GHC Team 1998-2002
  *
@@ -16,7 +16,8 @@
 #define NO_PRI  0
 #endif
 
-extern SchedulerStatus waitThread(StgTSO *main_thread, /*out*/StgClosure **ret);
+extern SchedulerStatus waitThread(StgTSO *main_thread, /*out*/StgClosure **ret,
+                                  Capability *initialCapability);
 
 /* 
  * Creating threads
@@ -30,7 +31,8 @@ extern StgTSO *createThread(nat stack_size);
 extern void taskStart(void);
 #endif
 extern void scheduleThread(StgTSO *tso);
-extern SchedulerStatus scheduleWaitThread(StgTSO *tso, /*out*/HaskellObj* ret);
+extern SchedulerStatus scheduleWaitThread(StgTSO *tso, /*out*/HaskellObj* ret,
+                                          Capability *initialCapability);
 
 static inline void pushClosure   (StgTSO *tso, StgWord c) {
   tso->sp--;