diff --git a/include/ck_hs.h b/include/ck_hs.h
index b3eb046..3c12b6e 100644
--- a/include/ck_hs.h
+++ b/include/ck_hs.h
@@ -100,10 +100,11 @@ struct ck_hs_stat {
 struct ck_hs_iterator {
 	void **cursor;
 	unsigned long offset;
+	struct ck_hs_map *map;
 };
 typedef struct ck_hs_iterator ck_hs_iterator_t;
 
-#define CK_HS_ITERATOR_INITIALIZER { NULL, 0 }
+#define CK_HS_ITERATOR_INITIALIZER { NULL, 0, NULL }
 
 /* Convenience wrapper to table hash function. */
 #define CK_HS_HASH(T, F, K) F((K), (T)->seed)
@@ -112,6 +113,7 @@ typedef void *ck_hs_apply_fn_t(void *, void *);
 bool ck_hs_apply(ck_hs_t *, unsigned long, const void *, ck_hs_apply_fn_t *, void *);
 void ck_hs_iterator_init(ck_hs_iterator_t *);
 bool ck_hs_next(ck_hs_t *, ck_hs_iterator_t *, void **);
+bool ck_hs_next_spmc(ck_hs_t *, ck_hs_iterator_t *, void **);
 bool ck_hs_move(ck_hs_t *, ck_hs_t *, ck_hs_hash_cb_t *,
     ck_hs_compare_cb_t *, struct ck_malloc *);
 bool ck_hs_init(ck_hs_t *, unsigned int, ck_hs_hash_cb_t *,
diff --git a/regressions/ck_hs/validate/serial.c b/regressions/ck_hs/validate/serial.c
index a16fc82..21cb13a 100644
--- a/regressions/ck_hs/validate/serial.c
+++ b/regressions/ck_hs/validate/serial.c
@@ -5,9 +5,9 @@
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
- * 1. Redistributions of source code must retain the above copyrighs
+ * 1. Redistributions of source code must retain the above copyrights
  *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyrighs
+ * 2. Redistributions in binary form must reproduce the above copyrights
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
@@ -58,11 +58,11 @@ static struct ck_malloc my_allocator = {
 };
 
 const char *test[] = { "Samy", "Al", "Bahra", "dances", "in", "the", "wind.", "Once",
-			"upon", "a", "time", "his", "gypsy", "ate", "one", "itsy",
-			    "bitsy", "spider.", "What", "goes", "up", "must",
-				"come", "down.", "What", "is", "down", "stays",
-				    "down.", "A", "B", "C", "D", "E", "F", "G", "H",
-					"I", "J", "K", "L", "M", "N", "O", "P", "Q" };
+                       "upon", "a", "time", "his", "gypsy", "ate", "one", "itsy",
+                       "bitsy", "spider.", "What", "goes", "up", "must",
+                       "come", "down.", "What", "is", "down", "stays",
+                       "down.", "A", "B", "C", "D", "E", "F", "G", "H",
+                       "I", "J", "K", "L", "M", "N", "O", "P", "Q" };
 
 const char *negative = "negative";
 
@@ -136,6 +136,7 @@ run_test(unsigned int is, unsigned int ad)
 	size_t i, j;
 	const char *blob = "#blobs";
 	unsigned long h;
+	ck_hs_iterator_t it;
 
 	if (ck_hs_init(&hs[0], CK_HS_MODE_SPMC | CK_HS_MODE_OBJECT | ad, hs_hash, hs_compare, &my_allocator, is, 6602834) == false)
 		ck_error("ck_hs_init\n");
@@ -181,6 +182,51 @@ run_test(unsigned int is, unsigned int ad)
 			}
 		}
 
+		/* Test iteration */
+		if (j == 0) { // avoid the blob stuff as it's not in the test array
+			ck_hs_iterator_init(&it);
+			void *k = NULL;
+			int matches = 0;
+			int entries = 0;
+			while(ck_hs_next(&hs[j], &it, &k)) {
+				entries++;
+				for (i = 0; i < sizeof(test) / sizeof(*test); i++) {
+					int x = strcmp(test[i], (char *)k);
+					if (x == 0) {
+						matches++;
+						break;
+					}
+				}
+			}
+
+			if (entries != matches) {
+				ck_error("Iteration must match all elements, has: %d, matched: %d [%d]", entries, matches, is);
+			}
+
+			/* Now test iteration in the face of grows (spmc)*/
+			ck_hs_iterator_init(&it);
+			k = NULL;
+			matches = 0;
+			entries = 0;
+			while(ck_hs_next_spmc(&hs[j], &it, &k)) {
+				entries++;
+				for (i = 0; i < sizeof(test) / sizeof(*test); i++) {
+					int x = strcmp(test[i], (char *)k);
+					if (x == 0) {
+						matches++;
+						break;
+					}
+				}
+				if (entries == 20) {
+					ck_hs_grow(&hs[j], 128);
+				}
+			}
+
+			if (entries != matches) {
+				ck_error("After growth, iteration must match all elements, has: %d, matched: %d [%d]", entries, matches, is);
+			}
+		}
+
 		/* Test grow semantics. */
 		ck_hs_grow(&hs[j], 128);
 		for (i = 0; i < sizeof(test) / sizeof(*test); i++) {
diff --git a/src/ck_hs.c b/src/ck_hs.c
index 31510ec..86d04ed 100644
--- a/src/ck_hs.c
+++ b/src/ck_hs.c
@@ -105,21 +105,10 @@ ck_hs_map_signal(struct ck_hs_map *map, unsigned long h)
 	return;
 }
 
-void
-ck_hs_iterator_init(struct ck_hs_iterator *iterator)
+static bool 
+_ck_hs_next(struct ck_hs *hs, struct ck_hs_map *map, struct ck_hs_iterator *i, void **key)
 {
-
-	iterator->cursor = NULL;
-	iterator->offset = 0;
-	return;
-}
-
-bool
-ck_hs_next(struct ck_hs *hs, struct ck_hs_iterator *i, void **key)
-{
-	struct ck_hs_map *map = hs->map;
 	void *value;
-
 	if (i->offset >= map->capacity)
 		return false;
 
@@ -129,6 +118,8 @@ ck_hs_next(struct ck_hs *hs, struct ck_hs_iterator *i, void **key)
 #ifdef CK_HS_PP
 			if (hs->mode & CK_HS_MODE_OBJECT)
 				value = CK_HS_VMA(value);
+#else
+			(void)hs; // avoid unused param warning
 #endif
 			i->offset++;
 			*key = value;
@@ -139,6 +130,32 @@ ck_hs_next(struct ck_hs *hs, struct ck_hs_iterator *i, void **key)
 	return false;
 }
 
+void
+ck_hs_iterator_init(struct ck_hs_iterator *iterator)
+{
+
+	iterator->cursor = NULL;
+	iterator->offset = 0;
+	iterator->map = NULL;
+	return;
+}
+
+bool
+ck_hs_next(struct ck_hs *hs, struct ck_hs_iterator *i, void **key)
+{
+	return _ck_hs_next(hs, hs->map, i, key);
+}
+
+bool
+ck_hs_next_spmc(struct ck_hs *hs, struct ck_hs_iterator *i, void **key)
+{
+	struct ck_hs_map *m = i->map;
+	if (m == NULL) {
+		m = i->map = ck_pr_load_ptr(&hs->map);
+	}
+	return _ck_hs_next(hs, m, i, key);
+}
+
 void
 ck_hs_stat(struct ck_hs *hs, struct ck_hs_stat *st)
 {