+.. option:: merge_blktrace_scalars=float_list
+
+ This is a percentage based option that is index paired with the list of
+ files passed to :option:`read_iolog`. When merging is performed, scale
+ the time of each event by the corresponding amount. For example,
+ ``--merge_blktrace_scalars="50:100"`` runs the first trace in halftime
+ and the second trace in realtime. This knob is separately tunable from
+ :option:`replay_time_scale` which scales the trace during runtime and
+ does not change the output of the merge unlike this option.
+
+.. option:: merge_blktrace_iters=float_list
+
+ This is a whole number option that is index paired with the list of files
+ passed to :option:`read_iolog`. When merging is performed, run each trace
+ for the specified number of iterations. For example,
+ ``--merge_blktrace_iters="2:1"`` runs the first trace for two iterations
+ and the second trace for one iteration.
+