Memory Access

+2 votes

A CPU has a 2 level cache with hit ratio of L1 and L2 cache as 90% and 95% respecrtively. Also the access time of L1 and L2 is 1ns and 5ns respectivelly.If access time of main memory is 50ns .then EAT(Effective Access Time ) is ....

My Solution :  Since nothing is mentioned in the questin about the condition of the cache I took the deafult case

 0.90*1 + 0.10*0.95(5) + 0.10*0.05*50 = 1.625

But the Solution given has assumed it to be Hierarchail Access where we add Cache time in Miss part also        Solution given is  : 0.90*1 + 0.10*0.95*(5+1) + 0.10*0.05*(50+5+1) =1.75                                                                                     

So My Doubt is If nothing is mentioned in the question do we always have to take Hierarchial case or not ????

asked Dec 13, 2016 in Computer Organization by (3,200 points)

1 Answer

–1 vote

In the question it is itself mentioned 2 level which means only after checking first cache we will go to second. If level is not mentioned the we will take simultaneous.

answered Dec 29, 2016 by (280 points)