Parameter and Command Reference > Logging Configuration Parameters > LogOutputLogLevel 

LogOutputLogLevel 
Determines whether the log level is reported in the log. Enable this parameter to include the log level of a message in the log entry.
 
Logging and/or LogStream
If you set this parameter in the Logging and LogStream sections, the setting in the LogStream section takes precedence for the specified log stream.
LogLevel=Always
In this example, Always is added to the log message: