FFWD input is self-attention output. And since the output of self-attention layer is [context, d_model], FFWD layer input will grow as well. Consequently, FFWD layer compute cost will grow as well, no?
The cost of FFWD layer according to my calculations is ~(4+2 * true(w3)) * d_model * dff * n_layers * context_size so the FFWD cost grows linearly wrt the context size.
So, unless I misunderstood the transformer architecture, larger the context the larger the compute of both self-attention and FFWD is?