p0 comm_size 3
p0 bcast 5e8
p1 bcast 5e8
p2 bcast 5e8

p0 compute 5e8
p1 compute 2e8
p2 compute 5e8

p0 bcast 5e8
p1 bcast 5e8
p2 bcast 5e8

p0 compute 5e8
p1 compute 2e8
p2 compute 5e8

p0 reduce 5e8 5e8
p1 reduce 5e8 5e8
p2 reduce 5e8 5e8