Alter the dmesg
Log Level¶
Where i
is 1 to 8 inclusive:
dmesg -n${i}
Only messages with a lower value will be reported on the console. - 1 - print only emergency messages - 8 - print all messages
All messages will still be added to the buffer, and are accessible via dmesg
.
Reducing the log level can help with maintaining performance while writing a lot of debug information.
Levels¶
See include/linux/kern_levels.h
:
- 0 -
KERN_EMERG
- system is unusable, cannot be masked - 1 -
KERN_ALERT
- action must be taken immediately - 2 -
KERN_CRIT
- critical conditions - 3 -
KERN_ERR
- error conditions - 4 -
KERN_WARNING
- warning conditions - 5 -
KERN_NOTICE
- normal but significant condition - 6 -
KERN_INFO
- informational - 7 -
KERN_DEBUG
- debug-level messages
Default¶
If you don't specify a log level in your message it defaults to KERN_DEFAULT
.
KERN_DEFAULT
(d
) can be configured via CONFIG_DEFAULT_MESSAGE_LOGLEVEL
, as defined in lib/Kconfig.debug
.