From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 3 Jan 2017 10:22:53 +0000 (+0100)
Subject: ntp: calculate delay relative to local frequency
X-Git-Tag: 3.0-pre3~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14bb9f29a3c2af359f8726ad00e2fa9e20394fc8;p=thirdparty%2Fchrony.git

ntp: calculate delay relative to local frequency

This should be more accurate as local frequency is usually
combined from multiple sources. This is a partial revert of commit
23a4e8b38d873ce1246c4ef43a05d92c442a9f26.
---

diff --git a/ntp_core.c b/ntp_core.c
index 00aee3f5..fd22cc00 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -1412,12 +1412,8 @@ receive_packet(NCR_Instance inst, NTP_Local_Address *local_addr,
       sample_rx_tss = rx_ts->source;
     }
 
-    /* Work out 'delay' relative to the source's time */
-    delay = (1.0 - (source_freq_lo + source_freq_hi) / 2.0) *
-              local_interval - remote_interval;
-
-    /* Clamp delay to avoid misleading results later */
-    delay = fabs(delay);
+    /* Calculate delay */
+    delay = fabs(local_interval - remote_interval);
     if (delay < precision)
       delay = precision;