Instruments - iOS Programming: The Big Nerd Ranch Guide - page 593

Click the info button next to the Allocations tool underneath the Stop button. This will
show a panel with the settings for the Allocations instrument: check the box for Record
reference counts ( Figure 21.13 ) .
Figure 21.13 Enable recording of reference counts
The Record reference counts option instructs Instruments to note every time an object
gains or loses an owner. Click the red Record button again to start profiling with this op-
tion turned on. ( Instruments can't build an application itself, so it uses the most recent
build from Xcode .)
Draw some lines in TouchTracker and then double-tap to delete them. Now select the
Line row and click the arrow next to it. Then select one of the Line instances that ap-
pear and click its arrow. This new table shows you the reference count history of an indi-
vidual Line object ( Figure 21.14 ).
Figure 21.14 Object's lifespan