count() or sum(). Use Unique Count
for tuple members if it is possible for values to repeat within the
column; Count is more efficent when tuple member values cannot
repeat because the aggregation key consists of only a single member,
such as pid in the following DTrace program statement:
@time[pid] = sum(timestamp - t);
Singular Total Label: Specifies the unit label appended to the column total when the total equals one. For example, if the singular total label is "process", and the total equals one, the value displayed in the total row is "1 process".
Plural Total Label: Specifies the unit label appended to the column total when the total is not equal to one. For example, if the plural total label is "processes", and the total equals three, the value displayed in the total row is "3 processes".
Format: Specifies a format string using
java.text.MessageFormat syntax. For example,
you could specify "cpu{0, number, integer}" to convert integer values 0
and 1 to "cpu0" and "cpu1". The format applies to column values and not
to the total row (if any).