Question

(C) Assume 500 instructions are executed using a four-stage pipeline. Each stage requires 1 clock cycle and each clock cycle lasts 2 nanoseconds. Andaikan suatu atur cara dengan 500 suruhan dilaksanakan pada talian paip suruhan dengan 4 tahap. Setiap tahap memerlukan 1 kitaran jam yang mengambil masa 2 nanosaat Calculate the speedup ratio. What is the maximum speedup that can be achieved? Kirakan nisbah "speedup". Apakah nilai "speedup" maksimum yang boleh dicapai. 0 4001 2000 cycle total (3/100) e lop 503 cycles total

Answer 1

Answer c

i)

# Cycles used by 1 Non-Pipeline Instruction = 4*1 = 4

so, # Cycles used by 500 Non-Pipeline Instruction = 4*500 = 2000

# Cycles used by 1 Pipeline Instruction = 4

so, # Cycles used by 500 Pipeline Instruction = 4 + (500-1) = 503

Speedup = 2000/503 = 3.976

ii)

Branch instructions causes 3 stall clock cycles.

Branch penalty = 0.1*3 = 0.3

So, # Cycles used by 500 Pipeline Instruction with branches = 503*1.3 = 653.9

Speedup = 2000/653.9 = 3.058