diff --git a/xs/sources/xsMapSet.c b/xs/sources/xsMapSet.c
index 8aefd1e3f2..9410d1e614 100644
--- a/xs/sources/xsMapSet.c
+++ b/xs/sources/xsMapSet.c
@@ -1034,6 +1034,9 @@ txBoolean fxDeleteEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* key
 						address = &slot->next;
 					}
 				}
+#ifdef __XSNAP__
+				the->mapSetRemoveCount += 1;
+#endif
 				return 1;
 			}
 		}
@@ -1098,6 +1101,9 @@ void fxSetEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* key, txSlot
 	txSlot* first;
 	txSlot* last;
 	txSlot* slot;
+#ifdef __XSNAP__
+	txUnsigned qty = 0;
+#endif
 	while ((entry = *address)) {
 		if (entry->value.entry.sum == sum) {
 			first = entry->value.entry.slot;
@@ -1110,8 +1116,17 @@ void fxSetEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* key, txSlot
 				return;
 			}
 		}
+#ifdef __XSNAP__
+		qty += 1;
+#endif
 		address = &entry->next;
 	}
+#ifdef __XSNAP__
+	the->mapSetAddCount += 1;
+	if (qty > the->maxBucketSize) {
+		the->maxBucketSize = qty;
+	}
+#endif
 	first = fxNewSlot(the);
 	first->kind = key->kind;
 	first->value = key->value;
diff --git a/xs/sources/xsMemory.c b/xs/sources/xsMemory.c
index de115ad804..9e7b797925 100644
--- a/xs/sources/xsMemory.c
+++ b/xs/sources/xsMemory.c
@@ -331,7 +331,7 @@ void fxCollect(txMachine* the, txBoolean theFlag)
 		(long)(the->peakHeapCount * sizeof(txSlot)),
 		the->collectFlag & XS_TRASHING_FLAG);
 #endif
-#ifdef mxInstrument
+#if defined(mxInstrument) || defined(__XSNAP__)
 	the->garbageCollectionCount++;
 #endif
 #ifdef mxProfile
@@ -428,7 +428,7 @@ void fxGrowChunks(txMachine* the, txSize theSize)
 	if (!(the->collectFlag & XS_SKIPPED_COLLECT_FLAG)) {
 		txSize modulo = theSize % the->minimumChunksSize;
 		if (modulo)
-			fxAddChunkSizes(the, theSize, the->minimumChunksSize - modulo);
+			theSize = fxAddChunkSizes(the, theSize, the->minimumChunksSize - modulo);
 	}
 	theSize = fxAddChunkSizes(the, theSize, sizeof(txBlock));
 	aData = fxAllocateChunks(the, theSize);