diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 28e1380e44..7850c8d926 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -344,6 +344,22 @@ static boolean_t ztest_exiting;
 
 /* Global commit callback list */
 static ztest_cb_list_t zcl;
+/* Commit cb delay */
+static uint64_t zc_min_txg_delay = UINT64_MAX;
+static int zc_cb_counter = 0;
+
+/*
+ * Minimum number of commit callbacks that need to be registered for us to check
+ * whether the minimum txg delay is acceptable.
+ */
+#define	ZTEST_COMMIT_CB_MIN_REG	100
+
+/*
+ * If a number of txgs equal to this threshold have been created after a commit
+ * callback has been registered but not called, then we assume there is an
+ * implementation bug.
+ */
+#define	ZTEST_COMMIT_CB_THRESH	(TXG_CONCURRENT_STATES + 1000)
 
 extern uint64_t metaslab_gang_bang;
 extern uint64_t metaslab_df_alloc_threshold;
@@ -4192,18 +4208,20 @@ ztest_commit_callback(void *arg, int error)
 		return;
 	}
 
-	/* Was this callback added to the global callback list? */
-	if (!data->zcd_added)
-		goto out;
-
+	ASSERT(data->zcd_added);
 	ASSERT3U(data->zcd_txg, !=, 0);
 
-	/* Remove our callback from the list */
 	(void) mutex_enter(&zcl.zcl_callbacks_lock);
+
+	/* See if this cb was called more quickly */
+	if ((synced_txg - data->zcd_txg) < zc_min_txg_delay)
+		zc_min_txg_delay = synced_txg - data->zcd_txg;
+
+	/* Remove our callback from the list */
 	list_remove(&zcl.zcl_callbacks, data);
+
 	(void) mutex_exit(&zcl.zcl_callbacks_lock);
 
-out:
 	umem_free(data, sizeof (ztest_cb_data_t));
 }
 
@@ -4222,13 +4240,6 @@ ztest_create_cb_data(objset_t *os, uint64_t txg)
 	return (cb_data);
 }
 
-/*
- * If a number of txgs equal to this threshold have been created after a commit
- * callback has been registered but not called, then we assume there is an
- * implementation bug.
- */
-#define	ZTEST_COMMIT_CALLBACK_THRESH	(TXG_CONCURRENT_STATES + 2)
-
 /*
  * Commit callback test.
  */
@@ -4240,7 +4251,7 @@ ztest_dmu_commit_callbacks(ztest_ds_t *zd, uint64_t id)
 	dmu_tx_t *tx;
 	ztest_cb_data_t *cb_data[3], *tmp_cb;
 	uint64_t old_txg, txg;
-	int i, error;
+	int i, error = 0;
 
 	od = umem_alloc(sizeof(ztest_od_t), UMEM_NOFAIL);
 	ztest_od_init(od, id, FTAG, 0, DMU_OT_UINT64_OTHER, 0, 0);
@@ -4324,7 +4335,7 @@ ztest_dmu_commit_callbacks(ztest_ds_t *zd, uint64_t id)
 	 */
 	tmp_cb = list_head(&zcl.zcl_callbacks);
 	if (tmp_cb != NULL &&
-	    tmp_cb->zcd_txg > txg - ZTEST_COMMIT_CALLBACK_THRESH) {
+	    tmp_cb->zcd_txg + ZTEST_COMMIT_CB_THRESH < txg) {
 		fatal(0, "Commit callback threshold exceeded, oldest txg: %"
 		    PRIu64 ", open txg: %" PRIu64 "\n", tmp_cb->zcd_txg, txg);
 	}
@@ -4355,6 +4366,8 @@ ztest_dmu_commit_callbacks(ztest_ds_t *zd, uint64_t id)
 		tmp_cb = cb_data[i];
 	}
 
+	zc_cb_counter += 3;
+
 	(void) mutex_exit(&zcl.zcl_callbacks_lock);
 
 	dmu_tx_commit(tx);
@@ -5372,6 +5385,10 @@ ztest_run(ztest_shared_t *zs)
 	for (object = 1; object < 50; object++)
 		dmu_prefetch(spa->spa_meta_objset, object, 0, 1ULL << 20);
 
+	/* Verify that at least one commit cb was called in a timely fashion */
+	if (zc_cb_counter >= ZTEST_COMMIT_CB_MIN_REG)
+		VERIFY3U(zc_min_txg_delay, ==, 0);
+
 	spa_close(spa, FTAG);
 
 	/*
diff --git a/module/zfs/txg.c b/module/zfs/txg.c
index 4ed812b440..f4eac8b585 100644
--- a/module/zfs/txg.c
+++ b/module/zfs/txg.c
@@ -335,15 +335,15 @@ txg_dispatch_callbacks(dsl_pool_t *dp, uint64_t txg)
 			 * Commit callback taskq hasn't been created yet.
 			 */
 			tx->tx_commit_cb_taskq = taskq_create("tx_commit_cb",
-			    max_ncpus, minclsyspri, max_ncpus, max_ncpus * 2,
-			    TASKQ_PREPOPULATE);
+			    100, minclsyspri, max_ncpus, INT_MAX,
+			    TASKQ_THREADS_CPU_PCT | TASKQ_PREPOPULATE);
 		}
 
 		cb_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
 		list_create(cb_list, sizeof (dmu_tx_callback_t),
 		    offsetof(dmu_tx_callback_t, dcb_node));
 
-		list_move_tail(&tc->tc_callbacks[g], cb_list);
+		list_move_tail(cb_list, &tc->tc_callbacks[g]);
 
 		(void) taskq_dispatch(tx->tx_commit_cb_taskq, (task_func_t *)
 		    txg_do_callbacks, cb_list, TQ_SLEEP);