[Linuxptp-devel] [PATCH RFC 6/6] pi: use sample weight.

[Miroslav L. <mli...@re...>]

Signed-off-by: Miroslav Lichvar <mli...@re...>
---
 pi.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/pi.c b/pi.c
index 9c7b148..a8c6051 100644
--- a/pi.c
+++ b/pi.c
@@ -61,6 +61,20 @@ static void pi_destroy(struct servo *servo)
 	free(s);
 }
 
+static int pi_weight_samples(struct servo *servo)
+{
+	struct pi_servo *s = container_of(servo, struct pi_servo, servo);
+
+	if (s->count < 2)
+		return 0;
+
+	/*
+	 * Enable weights approximately at half way between default ki
+	 * values for HW and SW time stamping.
+	 */
+	return s->ki <= 0.01;
+}
+
 static double pi_sample(struct servo *servo,
 			int64_t offset,
 			uint64_t local_ts,
@@ -137,8 +151,8 @@ static double pi_sample(struct servo *servo,
 			break;
 		}
 
-		ki_term = s->ki * offset;
-		ppb = s->kp * offset + s->drift + ki_term;
+		ki_term = s->ki * offset * weight;
+		ppb = s->kp * offset * weight + s->drift + ki_term;
 		if (ppb < -servo->max_frequency) {
 			ppb = -servo->max_frequency;
 		} else if (ppb > servo->max_frequency) {
@@ -186,6 +200,7 @@ struct servo *pi_servo_create(int fadj, int sw_ts)
 		return NULL;
 
 	s->servo.destroy = pi_destroy;
+	s->servo.weight_samples = pi_weight_samples;
 	s->servo.sample  = pi_sample;
 	s->servo.sync_interval = pi_sync_interval;
 	s->servo.reset   = pi_reset;
-- 
2.1.0