The rules in DEFS-FILE should have the format shown below:
event_id whitespace format
Each rule should start on a new line.
The format string may include format specifiers, such as: %(cpu)d, %(tsc)d, %(event)d, %(1)d, %(2)d, %(3)d, %(4)d, %(5)d
[ the `d' format specifier output in decimal, alternatively `x'
will output in hexadecimal and `o' will output in octal ]
These correspond to the CPU number, event ID, timestamp counter and the 5 data fields from the trace record. There should be one such rule for each type of event to be pretty-printed (events which do not have formatting rules are ignored).
A sample format file for Xen's predefined trace events is available in the file tools/xentrace/formats in the Xen source tree.
Depending on your system and the rate at which trace data is produced, this script may not be able to keep up with the output of xentrace if it is piped directly. In these circumstances you should have xentrace output to a file for processing off-line.