attribute cascade_height : integer;
attribute cascade_height of my_ram signal is 16;
In addition to the attributes that only affect the specific RAMs on which they are put, there is also a global setting which affects all RAMs in the design.
The Synthesis Settings menu has the -max_uram_cascade_height setting. The default value is -1 which means that the Vivado synthesis tool determines the best course of action, but this can be overridden by other values. In case of a conflict between the global setting and a CASCADE_HEIGHT attribute, the attribute is used for that specific RAM.