From 2f44ad86f5553edb9e7854767424f22ba132ee92 Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Sat, 7 May 2022 09:49:22 -0600 Subject: [PATCH] dmesg: Better wording from review I pushed the last changes before I'd noticed the better wording suggestions in the review. Also include a note that not all lines will have a timestampe. Some multi-line messages are generated with sbuf, and when those are pushed, only the first line will have the timestamp. Document this quirky behavior as well since fixing it likely won't happen soon. CAM periph drivers generate all the lines in their announce message together so they aren't intermingled with other things, for example. Suggested by: allanjude, emaste, rpokala Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D35139 Differential Revision: https://reviews.freebsd.org/D35141 --- sbin/dmesg/dmesg.8 | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/sbin/dmesg/dmesg.8 b/sbin/dmesg/dmesg.8 index a924549264cd..50b5e3e26404 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 May 6, 2022 +.Dd May 7, 2022 .Dt DMESG 8 .Os .Sh NAME @@ -73,8 +73,7 @@ which is the kernel image the system has booted from. .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: +variables control how the kernel timestamps entries in the message buffer: The default value is shown next to each variable. .Bl -tag -width indent .It kern.msgbuf_show_timestamp : No 0 @@ -85,6 +84,8 @@ If set to 2, then a microsecond granularity timestamp will be added. This may also be set as a boot .Xr loader 8 tunable. +The timestamps are placed at the start of most lines that the kernel generates. +Some multi-line messages will have only the first line tagged with a timestamp. .El .Sh FILES .Bl -tag -width ".Pa /var/run/dmesg.boot" -compact