first cut at multi-threading version

src/ca/flow_control.cpp

@@ -0,0 +1,76 @@
+/* $Id$ */
+/*
+ *
+ *                    L O S  A L A M O S
+ *              Los Alamos National Laboratory
+ *               Los Alamos, New Mexico 87545
+ *
+ *  Copyright, 1986, The Regents of the University of California.
+ *
+ *  Author: Jeff Hill
+ */	
+
+#include		"iocinf.h"
+
+/*
+ * FLOW CONTROL
+ * 
+ * Keep track of how many times messages have 
+ * come with out a break in between and 
+ * suppress monitors if we are behind
+ * (an update is sent when we catch up)
+ */
+
+void flow_control_on (tcpiiu *piiu)
+{
+	int status;
+
+	LOCK (piiu->niiu.iiu.pcas);
+
+	/*	
+	 * I prefer to avoid going into flow control 
+	 * as this impacts the performance of batched fetches
+	 */
+	if (piiu->contiguous_msg_count >= MAX_CONTIGUOUS_MSG_COUNT) {
+		if (!piiu->client_busy) {
+			status = ca_busy_message(piiu);
+			if (status==ECA_NORMAL) {
+				assert(piiu->niiu.iiu.pcas->ca_number_iiu_in_fc<UINT_MAX);
+				piiu->niiu.iiu.pcas->ca_number_iiu_in_fc++;
+				piiu->client_busy = TRUE;
+#				if defined(DEBUG) 
+					printf("fc on\n");
+#				endif
+			}
+		}
+	}
+	else {
+		piiu->contiguous_msg_count++;
+	}
+
+	UNLOCK (piiu->niiu.iiu.pcas);
+	return;
+}
+
+void flow_control_off (tcpiiu *piiu)
+{
+	int    		status;
+
+	LOCK (piiu->niiu.iiu.pcas);
+
+	piiu->contiguous_msg_count = 0;
+	if (piiu->client_busy) {
+		status = ca_ready_message(piiu);
+		if (status==ECA_NORMAL) {
+			assert (piiu->niiu.iiu.pcas->ca_number_iiu_in_fc>0u);
+			piiu->niiu.iiu.pcas->ca_number_iiu_in_fc--;
+			piiu->client_busy = FALSE;
+#			if defined(DEBUG) 
+				printf("fc off\n");
+#			endif
+		}
+	}
+
+	UNLOCK (piiu->niiu.iiu.pcas);
+	return;
+}