Pipeline Bubble Fraction

Problem

Compute the pipeline bubble fraction for GPipe-style scheduling: (num_stages - 1) / (num_microbatches + num_stages - 1).

The signature is pipeline_bubble_fraction(num_stages, num_microbatches).

Hint

More micro-batches per step shrink the idle bubble at the pipeline start and end.

case 1

in: [4,8]

expected: 0.2727272727

case 2

in: [4,1]

expected: 0.75

case 3

in: [1,10]

expected: 0

case 4

in: [8,32]

expected: 0.1794871795

Starter codePython

def pipeline_bubble_fraction(num_stages, num_microbatches):
    # Your code here
    pass

4 test cases · run your code against them in the editor