Thomas' Tech Tips

How to enable timestamps in dmesg

30 October 2022 - Thomas Damgaard

Wheder timestamps are shown or not is controlled by /sys/module/printk/parameters/time

To enable timestamps in dmesg, run

echo 1 >  /sys/module/printk/parameters/time

To disable timestamps in dmesg, run

echo 0 >  /sys/module/printk/parameters/time

Alternatively, you can use the following options when invoking dmesg:

 -d, --show-delta            show time delta between printed messages
 -e, --reltime               show local time and time delta in readable format
 -T, --ctime                 show human-readable timestamp (may be inaccurate!)
 -t, --notime                don't show any timestamp with messages
     --time-format <format>  show timestamp using the given format:
                               [delta|reltime|ctime|notime|iso]

Note: Suspending/resume will make ctime and iso timestamps inaccurate.

Filed under: linux, tips