@@ -1502,10 +1502,12 @@
 ;;
 (define *max-tries-hash* (make-hash-table))
 
 (define (runs:pretty-long-list lst)
    (if (> (length lst) 8)(append (take lst 3)(list "...")) lst))
+
+(define *last-loop-time-ms* 0)
 
 ;;======================================================================
 ;; runs:run-tests-queue is called by runs:run-tests
 ;;======================================================================
 ;;
@@ -1640,10 +1642,22 @@
 			   testmode:    testmode
 			   newtal:      newtal
 			   itemmaps:    itemmaps
 			   ;; prereqs-not-met: prereqs-not-met
 			   )))
+
+	;; too-tight loop detection and delay, this might hide issues
+	;; that occur in long run times. Consider commenting when debugging
+	;; 
+	(if (and (>= num-running max-concurrent-jobs)
+		 (< (- (current-milliseconds) *last-loop-time-ms*) 500))
+	    (begin
+	      (if (runs:lownoise "too-tight-loop" 5)
+		  (debug:print-info 2 *default-log-port* "Excessively fast loop, delaying 1/2 second"))
+	      (thread-sleep! 0.5)))
+	(set! *last-loop-time-ms* (current-milliseconds))
+     
 	(runs:dat-regfull-set! runsdat regfull)
     
 	(if (> num-running 0)
             (set! last-time-some-running (current-seconds)))