CO-Pipelining-Q1

+1 vote

A pipeline of 2 stages with a delay of x units each is split to n stages. In the new design, each stage has a delay of x/n units. To get the throughput increase of 1700% what would be the n value?

asked Jun 12 in Computer Organization by gbmentor (7,990 points)
reshown Jun 13 by gbmentor

5 Answers

+2 votes
1700/100=17

17+1=18

n=18
answered Jun 13 by tsnikhilsharmagate2018 (7,480 points)
0 votes
please someone solve
answered 6 days ago by ravipro20 (150 points)
+1 vote

let initial throughput be 100. required throughput is 1800.

speedup = 1800/100 = 18

In the first pipeline, each instruction will get completed after x units, and in the second pipeline, each instruction will get completed after x/n units

speedup = x / (x/n)

                = n

                therefore n = 18

 

answered 6 days ago by tsabhineetsingh192 (280 points)
0 votes

Comment if you find any issues. 

Pipeline 1

One instruction <----- x units 
? <-------------------------1 unit 

= \frac{1}{x} units

Pipeline 2 

One instruction ----> x/n units 

? -----------------------> 1 units 
= \frac{n}{x} units

percentage \ of \ gain\ in \ throughput = \frac{old value- new value}{old value} * 100

1700 = (n-1)* 100 

17 = n-1 

18=n 

 

 

 

answered 6 days ago by getgatebook (22,170 points)
edited 4 days ago by getgatebook
In pipeline 1, stage delay= x units. If we consider the CPI(cycles per instruction as 1), which is considered until no stalls are given.

Thus each instruction takes x time units.

Throughput in Pipeline 1 = 1/x

Similarly, every instruction in pipeline 2 takes x/n time units.

Thus, throughput in pipeline 2 = 1/(x/n) = n/x

% increase in throughput = ((new-old)/old)*100

                          1700       =(((n/x)-(1/x))/(1/x)*100
                                       
                           17           =n-1

                            18           = n
Yes you are correct. corrected the answer.
In this question (http://thegatebook.in/qa/4507) the throughput is (no. of stages / max stage time) so why in the above question. its only 1/x?
Please correct the answer, it is still showing 6.
0 votes
n=18 should be answer
answered 4 days ago by tskukrejakapil7 (160 points)
Answer:
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