Changeset: d665ecc5f37e for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=d665ecc5f37e
Modified Files:
monetdb5/mal/mal_dataflow.c
Branch: default
Log Message:
Produce exception when you can not create threads
The dataflow initialization routine assumed that it is always
possible to spawn a new thread. There is no such guarantee.
At least an exception should be raised when this happens.
diffs (49 lines):
diff --git a/monetdb5/mal/mal_dataflow.c b/monetdb5/mal/mal_dataflow.c
--- a/monetdb5/mal/mal_dataflow.c
+++ b/monetdb5/mal/mal_dataflow.c
@@ -352,22 +352,30 @@ DFLOWworker(void *t)
* Create a set of DFLOW interpreters.
* One worker will adaptively be available for each client.
* The remainder are taken from the GDKnr_threads argument and
- * typically is equal to the number of cores
+ * typically is equal to the number of cores.
+ * A recursive MAL function call would make for one worker less,
+ * which limits the number of cores for parallel processing.
* The workers are assembled in a local table to enable debugging.
*/
-static void
+static str
DFLOWinitialize(void)
{
int i, limit;
if (todo)
- return;
+ return MAL_SUCCEED;
MT_lock_set(&mal_contextLock, "DFLOWinitialize");
todo = q_create(2048, "todo");
limit = GDKnr_threads ? GDKnr_threads : 1;
- for (i = 0; i < limit; i++)
+ for (i = 0; i < limit && i < THREADS; i++) {
MT_create_thread(&workers[i], DFLOWworker, (void *)
&workers[i], MT_THR_JOINABLE);
+ if ( workers[i] == 0 ) {
+ MT_lock_unset(&mal_contextLock, "DFLOWinitialize");
+ throw(MAL, "dataflow", "Can not create interpreter
thread");
+ }
+ }
MT_lock_unset(&mal_contextLock, "DFLOWinitialize");
+ return MAL_SUCCEED;
}
/*
@@ -586,7 +594,9 @@ runMALdataflow(Client cntxt, MalBlkPtr m
/* check existence of workers */
if (workers[0] == 0)
- DFLOWinitialize();
+ ret = DFLOWinitialize();
+ if ( ret != MAL_SUCCEED)
+ return ret;
assert(workers[0]);
assert(todo);
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