Instruction Latencies: DAXPY Example
- There are 2 loads (x,y) and 1 store (y)= 3 mem ops.
- There are 2 fp operations (+,*) which can be done with 1 madd
- 3 mem ops require 3 cycles minimum (processor can do 1 mem op/cycle)
- theoretically in 3 cycles processor can do 6 fp operations
- only 2 fp operations are available in the code
- max processor speed is 2fp/6fp=1/3 peak on this code;
- I.e. for the R12000@300MHz processor 600/3=200 Mflop/s.