Improve efficiency of nullf servo synchronization

The nullf servo can now enter the SERVO_LOCKED_STABLE state by transitioning first to the SERVO_LOCKED state when the offset is less than the set value for offset_threshold. If offset_threshold is not set, the SERVO_LOCKED state can be entered when the offset is less than or equal to the set value for step_threshold. Signed-off-by: Rahul Rameshbabu <[email protected]>
lichenAAA · Feb 6, 2023 · 64e223c · 64e223c
1 parent 6e02bb2
commit 64e223c
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Showing 4 changed files with 23 additions and 20 deletions.
diff --git a/nullf.c b/nullf.c
@@ -38,14 +38,17 @@ static double nullf_sample(struct servo *servo, int64_t offset,
 			   uint64_t local_ts, double weight,
 			   enum servo_state *state)
 {
-	if (!offset) {
+	long long int abs_offset = llabs(offset);
+
+	if ((servo->offset_threshold && abs_offset < servo->offset_threshold) ||
+	    (servo->step_threshold && servo->step_threshold >= abs_offset)) {
 		*state = SERVO_LOCKED;
 		return 0.0;
 	}
 
 	if ((servo->first_update && servo->first_step_threshold &&
-	     servo->first_step_threshold < llabs(offset)) ||
-	    (servo->step_threshold && servo->step_threshold < llabs(offset))) {
+	     servo->first_step_threshold < abs_offset) ||
+	    (servo->step_threshold && servo->step_threshold < abs_offset)) {
 		*state = SERVO_JUMP;
 	} else {
 		*state = SERVO_UNLOCKED;

diff --git a/phc2sys.8 b/phc2sys.8
@@ -362,12 +362,12 @@ Same as option
 
 .TP
 .B step_threshold
-Specifies the step threshold of the servo. It is the maximum offset that
-the servo corrects by changing the clock frequency instead of stepping
-the clock. The clock is stepped on start regardless of the option if the
-offset is larger than 20 microseconds (unless the -F option is used).
-It's  specified  in seconds. The value of 0.0 disables stepping after
-the start. The default is 0.0.
+Specifies the step threshold of the servo. It is the maximum offset that the
+servo corrects by changing the clock frequency (phase when using nullf servo)
+instead of stepping the clock. The clock is stepped on start regardless of the
+option if the offset is larger than 20 microseconds (unless the -F option is
+used). It's specified in seconds. The value of 0.0 disables stepping after the
+start. The default is 0.0.
 Same as option
 .B \-S
 (see above).

diff --git a/ptp4l.8 b/ptp4l.8
@@ -591,18 +591,18 @@ the PI controller from the sync interval.
 The default is 0.3.
 .TP
 .B step_threshold
-The maximum offset the servo will correct by changing the clock
-frequency instead of stepping the clock. When set to 0.0, the servo will
-never step the clock except on start. It's specified in seconds.
+The maximum offset the servo will correct by changing the clock frequency (phase
+when using nullf servo) instead of stepping the clock. When set to 0.0, the
+servo will never step the clock except on start. It's specified in seconds.
 The default is 0.0.
 This option used to be called
 .BR pi_offset_const .
 .TP
 .B first_step_threshold
-The maximum offset the servo will correct by changing the clock
-frequency instead of stepping the clock. This is only applied on the first
-update. It's specified in seconds. When set to 0.0, the servo won't step
-the clock on start.
+The maximum offset the servo will correct by changing the clock frequency (phase
+when using nullf servo) instead of stepping the clock. This is only applied on
+the first update. It's specified in seconds. When set to 0.0, the servo won't
+step the clock on start.
 The default is 0.00002 (20 microseconds).
 This option used to be called
 .BR pi_f_offset_const .

diff --git a/ts2phc.8 b/ts2phc.8
@@ -119,10 +119,10 @@ command line option.
 
 .TP
 .B first_step_threshold
-The maximum offset, specified in seconds, that the servo will correct
-by changing the clock frequency instead of stepping the clock. This is
-only applied on the first update. When set to 0.0, the servo will not
-step the clock on start.
+The maximum offset, specified in seconds, that the servo will correct by
+changing the clock frequency (phase when using nullf servo) instead of stepping
+the clock. This is only applied on the first update. When set to 0.0, the servo
+will not step the clock on start.
 The default is 0.00002 (20 microseconds).
 .TP
 .B free_running