TotalView Online Help : Chapter 3 Variable Window : View Menu Commands : View > Padding
View > Padding
When selected, TotalView displays padding data that the compiler has added to data structures. (The compiler adds padding bits to data to force the alignment on to word boundaries.)
By default, TotalView does not display this information as errors caused by padding seldom occur. However, you may see errors due to padding if you miscast your data.