From 4f2fa2edabcc5807a879a6f60ecb2f28d5ad6085 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Wed, 18 Jul 2018 16:52:41 +0200 Subject: kernel: Improve net_ticktime docs --- lib/kernel/doc/src/kernel_app.xml | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) (limited to 'lib/kernel/doc/src') diff --git a/lib/kernel/doc/src/kernel_app.xml b/lib/kernel/doc/src/kernel_app.xml index 3914226a3e..ccb7d17d25 100644 --- a/lib/kernel/doc/src/kernel_app.xml +++ b/lib/kernel/doc/src/kernel_app.xml @@ -310,24 +310,31 @@ net_ticktime = TickTime -

Specifies the net_kernel tick time. TickTime - is specified in seconds. Once every TickTime/4 second, all - connected nodes are ticked (if anything else is written - to a node). If nothing is received from another node - within the last four tick times, that node is considered - to be down. This ensures that nodes that are not responding, - for reasons such as hardware errors, are considered to be - down.

-

The time T, in which a node that is not responding is - detected, is calculated as , where:

+

Specifies the net_kernel tick time in seconds. This is the + approximate time a connected node may be unresponsive until it is + considered down and thereby disconnected.

+

Once every TickTime/4 seconds, each connected node is ticked + if nothing has been sent to it during that last TickTime/4 + interval. A tick is a small package sent on the connection. A connected + node is considered to be down if no ticks or payload packages have been + received during the last four TickTime/4 intervals. This ensures + that nodes that are not responding, for reasons such as hardware errors, + are considered to be down.

+

As the availability is only checked every TickTime/4 seconds, + the actual time T a node have been unresponsive when + detected may vary between MinT and MaxT, + where:

MinT = TickTime - TickTime / 4 MaxT = TickTime + TickTime / 4 -

TickTime defaults to 60 (seconds). Thus, - seconds.

-

Notice that all communicating nodes are to have the same - TickTime value specified.

-

Normally, a terminating node is detected immediately.

+

TickTime defaults to 60 seconds. Thus, + seconds.

+

Notice that all communicating nodes are to have the + same TickTime value specified, as it determines both the + frequency of outgoing ticks and the expected frequency of incominging + ticks.

+

Normally, a terminating node is detected immediately by the transport + protocol (like TCP/IP).

shutdown_timeout = integer() | infinity -- cgit v1.2.3