[project @ 2003-10-01 10:49:07 by wolfgang]

Threaded RTS:
Don't start new worker threads earlier than necessary.
After this commit, a Haskell program that uses neither forkOS nor forkIO is
really single-threaded (rather than using two OS threads internally).

Some details:
Worker threads are now only created when a capability is released, and
only when
(there are no worker threads)
	&& (there are runnable Haskell threads ||
	    there are Haskell threads blocked on IO or threadDelay)
awaitEvent can now be called from bound thread scheduling loops
(so that we don't have to create a worker thread just to run awaitEvent)

1 files changed, 17 insertions, 1 deletions

diff --git a/ghc/rts/Select.c b/ghc/rts/Select.c
index 677fdd2c81..d7e6ffcdaa 100644
--- a/ghc/rts/Select.c
+++ b/ghc/rts/Select.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Select.c,v 1.29 2003/06/26 12:22:59 stolz Exp $
+ * $Id: Select.c,v 1.30 2003/10/01 10:49:09 wolfgang Exp $
  *
  * (c) The GHC Team 1995-2002
  *
@@ -351,4 +351,20 @@ wakeBlockedWorkerThread()
     	workerWakeupPending = rtsTrue;
     }
 }
+
+/* resetWorkerWakeupPipeAfterFork
+ *
+ * To be called right after a fork().
+ * After the fork(), the worker wakeup pipe will be shared
+ * with the parent process, and that's something we don't want.
+ */
+void
+resetWorkerWakeupPipeAfterFork()
+{
+    if(workerWakeupInited) {
+	close(workerWakeupPipe[0]);
+	close(workerWakeupPipe[1]);
+    }
+    workerWakeupInited = rtsFalse;
+}
 #endif