diff --git a/kern/test/synchprobs.c b/kern/test/synchprobs.c
index c1fc4db..1b5eaeb 100644
--- a/kern/test/synchprobs.c
+++ b/kern/test/synchprobs.c
@@ -77,10 +77,14 @@ male_wrapper(void * unused1, unsigned long unused2) {
 }
 void
 male_start(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s starting\n", curthread->t_name);
 }
 void
 male_end(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s ending\n", curthread->t_name);
 }
 
@@ -106,10 +110,14 @@ female_wrapper(void * unused1, unsigned long unused2) {
 }
 void
 female_start(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s starting\n", curthread->t_name);
 }
 void
 female_end(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s ending\n", curthread->t_name);
 }
 
@@ -135,10 +143,14 @@ matchmaker_wrapper(void * unused1, unsigned long unused2) {
 }
 void
 matchmaker_start(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s starting\n", curthread->t_name);
 }
 void
 matchmaker_end(void) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s ending\n", curthread->t_name);
 }
 
@@ -255,11 +267,15 @@ turnleft_wrapper(void *unused, unsigned long direction)
 
 void
 inQuadrant(int quadrant) {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s in quadrant %d\n", curthread->t_name, quadrant);
 }
 
 void
 leaveIntersection() {
+	random_yielder(PROBLEMS_MAX_YIELDER);
+	random_spinner(PROBLEMS_MAX_SPINNER);
 	tkprintf("%s left the intersection\n", curthread->t_name);
 }