naive packing — G = 4 rollouts
micro-batch
prompt (1,000 tok)
resp₁
prompt (1,000 tok)
resp₂
prompt (1,000 tok)
resp₃
prompt (1,000 tok)
resp₄
p2, p3, p4 are identical copies of p1 — wasted compute 3 × 1,000 = 3,000 extra
4,400 tokens processed
1,400 unique tokens