From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Wed, 10 Aug 2022 13:32:54 +0000 (+0200)
Subject: doc: mention maxdelayquant in FAQ
X-Git-Tag: 4.3-pre1~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=19b47dcbc9f07d028ac19e25bb8998a6cef5d9c3;p=thirdparty%2Fchrony.git

doc: mention maxdelayquant in FAQ
---

diff --git a/doc/faq.adoc b/doc/faq.adoc
index 732aa804..257e3010 100644
--- a/doc/faq.adoc
+++ b/doc/faq.adoc
@@ -345,6 +345,15 @@ server ntp.local minpoll -6 maxpoll -6 filter 15 xleave
 hwtimestamp eth0 minpoll -6
 ----
 
+Since `chrony` version 4.3, the minimum `minpoll` is -7 and a filter using a
+long-term estimate of a delay quantile can be enabled by the `maxdelayquant`
+option to replace the default `maxdelaydevratio` filter, which is sensitive to
+outliers corrupting the minimum delay. For example:
+
+----
+server ntp.local minpoll -7 maxpoll -7 filter 31 maxdelayquant 0.3 xleave
+----
+
 As an experimental feature added in version 4.2, `chronyd` supports an NTPv4
 extension field containing an additional timestamp to enable frequency transfer
 and significantly improve stability of synchronisation. It can be enabled by