GATE | GATE-CS-2015 (Set 3) | Question 61

Consider the following reservation table for a pipeline having three stages S1, S2 and S3.

     Time -->
-----------------------------
      1    2   3    4     5
-----------------------------
S1  | X  |   |   |    |  X |    
S2  |    | X |   | X  |    |
S3  |    |   | X |    |    |

The minimum average latency (MAL) is __________
(A) 3
(B) 2
(C) 1
(D) 4


Answer: (A)

Explanation:

S1 | X | Y |   |   | X | Y | X | Y |   |   | X | Y |
S2 | | X | Y | X | Y | | | X | Y | X | Y | |
S3 | | | X | Y | | | | | X | Y | | |



We can interleave instructions like the above
pattern.

Latency between X and Y is 1.

Latency between fist and second X is 5.

The pattern repeats after that.
So, MAL is (1 + 5)/2;


Quiz of this Question



My Personal Notes arrow_drop_up