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 hi2saifgmail-com (2,730 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 patel512 (280 points)