/* -----------------------------------------------------------------------------
- * $Id: Select.c,v 1.20 2002/07/09 20:44:24 sof Exp $
*
- * (c) The GHC Team 1995-1999
+ * (c) The GHC Team 1995-2002
*
* Support for concurrent non-blocking I/O and thread waiting.
*
* ---------------------------------------------------------------------------*/
+
/* we're outside the realms of POSIX here... */
/* #include "PosixSource.h" */
#include "Schedule.h"
#include "RtsUtils.h"
#include "RtsFlags.h"
+#include "Timer.h"
#include "Itimer.h"
#include "Signals.h"
+#include "Capability.h"
# ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
# include <sys/time.h>
# endif
-# ifdef mingw32_TARGET_OS
-# include <windows.h>
-# endif
+#include <errno.h>
+#include <string.h>
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
/* last timestamp */
-nat timestamp = 0;
+lnat timestamp = 0;
/* There's a clever trick here to avoid problems when the time wraps
* around. Since our maximum delay is smaller than 31 bits of ticks
* (idea due to Andy Gill).
*/
rtsBool
-wakeUpSleepingThreads(nat ticks)
+wakeUpSleepingThreads(lnat ticks)
{
StgTSO *tso;
rtsBool flag = rtsFalse;
sleeping_queue = tso->link;
tso->why_blocked = NotBlocked;
tso->link = END_TSO_QUEUE;
- IF_DEBUG(scheduler,belch("Waking up sleeping thread %d\n", tso->id));
+ IF_DEBUG(scheduler,debugBelch("Waking up sleeping thread %d\n", tso->id));
PUSH_ON_RUN_QUEUE(tso);
flag = rtsTrue;
}
StgTSO *tso, *prev, *next;
rtsBool ready;
fd_set rfd,wfd;
-#ifndef mingw32_TARGET_OS
int numFound;
int maxfd = -1;
-#endif
rtsBool select_succeeded = rtsTrue;
rtsBool unblock_all = rtsFalse;
- static rtsBool prev_unblocked_all = rtsFalse;
struct timeval tv;
lnat min, ticks;
tv.tv_usec = 0;
IF_DEBUG(scheduler,
- belch("scheduler: checking for threads blocked on I/O");
+ debugBelch("scheduler: checking for threads blocked on I/O");
if (wait) {
- belch(" (waiting)");
+ debugBelch(" (waiting)");
}
- belch("\n");
+ debugBelch("\n");
);
/* loop until we've woken up some threads. This loop is needed
min = 0x7ffffff;
}
-#ifndef mingw32_TARGET_OS
/*
* Collect all of the fd's that we're interested in
*/
}
}
- /* Release the scheduler lock while we do the poll.
- * this means that someone might muck with the blocked_queue
- * while we do this, but it shouldn't matter:
- *
- * - another task might poll for I/O and remove one
- * or more threads from the blocked_queue.
- * - more I/O threads may be added to blocked_queue.
- * - more delayed threads may be added to blocked_queue. We'll
- * just subtract delta from their delays after the poll.
- *
- * I believe none of these cases lead to trouble --SDM.
- */
- RELEASE_LOCK(&sched_mutex);
-
/* Check for any interesting events */
tv.tv_sec = min / 1000000;
should we see a bad file descriptor & give the threads
a chance to clean up their act.
- To avoid getting stuck in a loop, repeated EBADF failures
- are 'handled' through barfing.
+ Note: assume here that threads becoming unblocked
+ will try to read/write the file descriptor before trying
+ to issue a threadWaitRead/threadWaitWrite again (==> an
+ IOError will result for the thread that's got the bad
+ file descriptor.) Hence, there's no danger of a bad
+ file descriptor being repeatedly select()'ed on, so
+ the RTS won't loop.
*/
- if ( errno == EBADF && !prev_unblocked_all) {
+ if ( errno == EBADF ) {
unblock_all = rtsTrue;
- prev_unblocked_all = rtsTrue;
break;
} else {
- fprintf(stderr,"%d\n", errno);
- fflush(stderr);
perror("select");
barf("select failed");
}
}
-#else /* on mingwin */
- while (1) {
- Sleep(0); /* don't busy wait */
-#endif /* mingw32_TARGET_OS */
- ACQUIRE_LOCK(&sched_mutex);
-
- prev_unblocked_all = rtsFalse;
-#ifndef mingw32_TARGET_OS
/* We got a signal; could be one of ours. If so, we need
* to start up the signal handler straight away, otherwise
* we could block for a long time before the signal is
* serviced.
*/
+#if defined(RTS_USER_SIGNALS)
if (signals_pending()) {
- RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
startSignalHandlers();
- ACQUIRE_LOCK(&sched_mutex);
return; /* still hold the lock */
}
#endif
if (run_queue_hd != END_TSO_QUEUE) {
return; /* still hold the lock */
}
-
- RELEASE_LOCK(&sched_mutex);
}
- ACQUIRE_LOCK(&sched_mutex);
-
/* Step through the waiting queue, unblocking every thread that now has
* a file descriptor in a ready state.
*/
}
if (ready) {
- IF_DEBUG(scheduler,belch("Waking up blocked thread %d\n", tso->id));
+ IF_DEBUG(scheduler,debugBelch("Waking up blocked thread %d\n", tso->id));
tso->why_blocked = NotBlocked;
tso->link = END_TSO_QUEUE;
PUSH_ON_RUN_QUEUE(tso);
blocked_queue_tl = prev;
}
}
-
+
} while (wait && !interrupted && run_queue_hd == END_TSO_QUEUE);
}
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