**external**
Prefix to specify loading an external I/O engine object file. Append
the engine filename, e.g. ``ioengine=external:/tmp/foo.o`` to load
- ioengine :file:`foo.o` in :file:`/tmp`.
+ ioengine :file:`foo.o` in :file:`/tmp`. The path can be either
+ absolute or relative. See :file:`engines/skeleton_external.c` for
+ details of writing an external I/O engine.
I/O engine specific parameters
.. option:: clat_percentiles=bool
- Enable the reporting of percentiles of completion latencies.
+ Enable the reporting of percentiles of completion latencies. This
+ option is mutually exclusive with :option:`lat_percentiles`.
+
+.. option:: lat_percentiles=bool
+
+ Enable the reporting of percentiles of IO latencies. This is similar
+ to :option:`clat_percentiles`, except that this includes the
+ submission latency. This option is mutually exclusive with
+ :option:`clat_percentiles`.
.. option:: percentile_list=float_list