Answer all the parts 11 . Suppose we have a cached system with the following par

Question

Answer all the parts

11. Suppose we have a cached system with the following parameters:

tc =100ns tm =1000ns
h = 0.90 Block size = 8 words Main memory to cache connection = 2 words

(a) Calculate the effective memory access time if a read through policy is used.

(b) Calculate the effective memory access time if no read through policy is used. Assume that, upon a cache miss, the replaced cache block is first transferred to main memory, the requested block is then loaded into the cache, and then the selected word is accessed from the cache.

(c) Same as part (b) except that a no write allocate policy is used on a write miss. That is, the word is modified in main memory but the block is not loaded into the cache. Assume 30% of all accesses are writes. Recall that no write allocate does not imply anything about policies on write hits – all it says is what happens upon a cache miss.

Explanation / Answer

(a) Tc = Time for cache, Tm = Time for main memory access.

(b) As main memory to cache, it needs 2 words, hence tm = 1000*2 = 2000ns

(c) 30% writes, so hit ratio for write is 0.3

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.