diff --git a/config.c b/config.c
index aa856ad..6732b23 100644
--- a/config.c
+++ b/config.c
@@ -61,6 +61,14 @@ struct config_item {
 
 #define N_CONFIG_ITEMS (sizeof(config_tab) / sizeof(config_tab[0]))
 
+#define CONFIG_ITEM_DBL(_label, _port, _default, _min, _max) {	\
+	.label	= _label,				\
+	.type	= CFG_TYPE_DOUBLE,			\
+	.flags	= _port ? CFG_ITEM_PORT : 0,		\
+	.val.d	= _default,				\
+	.min.d	= _min,					\
+	.max.d	= _max,					\
+}
 #define CONFIG_ITEM_INT(_label, _port, _default, _min, _max) {	\
 	.label	= _label,				\
 	.type	= CFG_TYPE_INT,				\
@@ -70,15 +78,22 @@ struct config_item {
 	.max.i	= _max,					\
 }
 
+#define GLOB_ITEM_DBL(label, _default, min, max) \
+	CONFIG_ITEM_DBL(label, 0, _default, min, max)
+
 #define GLOB_ITEM_INT(label, _default, min, max) \
 	CONFIG_ITEM_INT(label, 0, _default, min, max)
 
+#define PORT_ITEM_DBL(label, _default, min, max) \
+	CONFIG_ITEM_DBL(label, 1, _default, min, max)
+
 #define PORT_ITEM_INT(label, _default, min, max) \
 	CONFIG_ITEM_INT(label, 1, _default, min, max)
 
 struct config_item config_tab[] = {
 	GLOB_ITEM_INT("assume_two_step", 0, 0, 1),
 	GLOB_ITEM_INT("check_fup_sync", 0, 0, 1),
+	GLOB_ITEM_DBL("step_threshold", 0.0, 0.0, DBL_MAX),
 	GLOB_ITEM_INT("tx_timestamp_timeout", 1, 1, INT_MAX),
 	PORT_ITEM_INT("udp_ttl", 1, 1, 255),
 };
@@ -569,12 +584,6 @@ static enum parser_result parse_global_setting(const char *option,
 			return r;
 		*cfg->pi_integral_norm_max = df;
 
-	} else if (!strcmp(option, "step_threshold")) {
-		r = get_ranged_double(value, &df, 0.0, DBL_MAX);
-		if (r != PARSED_OK)
-			return r;
-		*cfg->step_threshold = df;
-
 	} else if (!strcmp(option, "first_step_threshold")) {
 		r = get_ranged_double(value, &df, 0.0, DBL_MAX);
 		if (r != PARSED_OK)
diff --git a/config.h b/config.h
index 4538b4e..45805de 100644
--- a/config.h
+++ b/config.h
@@ -72,7 +72,6 @@ struct config {
 	struct port_defaults pod;
 	enum servo_type clock_servo;
 
-	double *step_threshold;
 	double *first_step_threshold;
 	int *max_frequency;
 
diff --git a/phc2sys.c b/phc2sys.c
index 45ae363..fa75607 100644
--- a/phc2sys.c
+++ b/phc2sys.c
@@ -1222,11 +1222,12 @@ int main(int argc, char *argv[])
 	char *progname;
 	char *src_name = NULL, *dst_name = NULL;
 	struct clock *src, *dst;
+	struct config *cfg;
 	int autocfg = 0, rt = 0;
 	int c, domain_number = 0, pps_fd = -1;
 	int r, wait_sync = 0;
 	int print_level = LOG_INFO, use_syslog = 1, verbose = 0;
-	double phc_rate;
+	double phc_rate, tmp;
 	struct node node = {
 		.sanity_freq_limit = 200000000,
 		.servo_type = CLOCK_SERVO_PI,
@@ -1240,6 +1241,7 @@ int main(int argc, char *argv[])
 	if (config_init(&phc2sys_config)) {
 		return -1;
 	}
+	cfg = &phc2sys_config;
 
 	configured_pi_kp = KP;
 	configured_pi_ki = KI;
@@ -1297,8 +1299,9 @@ int main(int argc, char *argv[])
 				return -1;
 			break;
 		case 'S':
-			if (get_arg_val_d(c, optarg, &servo_step_threshold,
-					  0.0, DBL_MAX))
+			if (get_arg_val_d(c, optarg, &tmp, 0.0, DBL_MAX))
+				return -1;
+			if (config_set_double(cfg, "step_threshold", tmp))
 				return -1;
 			break;
 		case 'F':
diff --git a/ptp4l.c b/ptp4l.c
index b2ac0d5..3b913c0 100644
--- a/ptp4l.c
+++ b/ptp4l.c
@@ -103,7 +103,6 @@ static struct config cfg_settings = {
 	.transport = TRANS_UDP_IPV4,
 	.clock_servo = CLOCK_SERVO_PI,
 
-	.step_threshold = &servo_step_threshold,
 	.first_step_threshold = &servo_first_step_threshold,
 	.max_frequency = &servo_max_frequency,
 
diff --git a/servo.c b/servo.c
index aa71b21..f1eddc8 100644
--- a/servo.c
+++ b/servo.c
@@ -18,6 +18,7 @@
  */
 #include <string.h>
 
+#include "config.h"
 #include "linreg.h"
 #include "ntpshm.h"
 #include "nullf.h"
@@ -26,13 +27,13 @@
 
 #define NSEC_PER_SEC 1000000000
 
-double servo_step_threshold = 0.0;
 double servo_first_step_threshold = 0.00002; /* 20 microseconds */
 int servo_max_frequency = 900000000;
 
 struct servo *servo_create(struct config *cfg, enum servo_type type,
 			   int fadj, int max_ppb, int sw_ts)
 {
+	double servo_step_threshold;
 	struct servo *servo;
 
 	switch (type) {
@@ -52,6 +53,7 @@ struct servo *servo_create(struct config *cfg, enum servo_type type,
 		return NULL;
 	}
 
+	servo_step_threshold = config_get_double(cfg, NULL, "step_threshold");
 	if (servo_step_threshold > 0.0) {
 		servo->step_threshold = servo_step_threshold * NSEC_PER_SEC;
 	} else {
diff --git a/servo.h b/servo.h
index cc0b098..88d926b 100644
--- a/servo.h
+++ b/servo.h
@@ -24,15 +24,6 @@
 
 struct config;
 
-/**
- * When set to a non-zero value, this variable controls the maximum allowed
- * offset before a clock jump occurs instead of the default clock-slewing
- * mechanism.
- *
- * Note that this variable is measured in seconds, and allows fractional values.
- */
-extern double servo_step_threshold;
-
 /**
  * When set to zero, the clock is not stepped on start. When set to a non-zero
  * value, the value bahaves as a threshold and the clock is stepped on start if