git: 6910fee62e77 - main - dmesg: Document kern.msgbuf_show_timestamp

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=6910fee62e77afecbaff3be0ff922a34e85a9881

commit 6910fee62e77afecbaff3be0ff922a34e85a9881
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2022-05-06 16:32:10 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2022-05-07 15:32:21 +0000

    dmesg: Document kern.msgbuf_show_timestamp
    
    kern.msgbuf_show_timestamp=1 turns on timestamps in kernel's message
    buffer which dmesg(8) prints.
    
    Sponsored by:           Netflix
---
 sbin/dmesg/dmesg.8 | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/sbin/dmesg/dmesg.8 b/sbin/dmesg/dmesg.8
index e40d8d5c9ff7..13101baf7e78 100644
--- a/sbin/dmesg/dmesg.8
+++ b/sbin/dmesg/dmesg.8
@@ -28,7 +28,7 @@
 .\"     @(#)dmesg.8	8.1 (Berkeley) 6/5/93
 .\" $FreeBSD$
 .\"
-.Dd October 3, 2016
+.Dd May 6, 2022
 .Dt DMESG 8
 .Os
 .Sh NAME
@@ -70,6 +70,19 @@ is also specified,
 extract the name list from the specified system instead of the default,
 which is the kernel image the system has booted from.
 .El
+.Sh SYSCTL VARIABLES
+The following
+.Xr sysctl 8
+variables can be used to control the behavior of the kernel's placing data into
+the message buffer:
+The default value is shown next to each variable.
+.Bl -tag -width indent
+.It  kern.msgbuf_show_timestamp : No 0
+If set to 1, then a timestamp will be added to most lines in the message buffer.
+This may also be set as a boot
+.Xr loader 8
+tunable.
+.El
 .Sh FILES
 .Bl -tag -width ".Pa /var/run/dmesg.boot" -compact
 .It Pa /var/run/dmesg.boot