A direct-mapped cache consists of 16 blocks. A byte-addressable main memory contains 4K blocks of 16 bytes each. Access time for the cache is 30 ns and the time required to fill a cache slot from main memory is 250 ns. Assume a request is always started in sequential to cache and then to main memory. If a block is missing from cache, the entire block is brought into the cache and the access is restarted. Initially, the cache is empty. a) Show the main memory address format that allows us to map addresses from main memory to cache. Be sure to include the fields as well as their sizes. b) Compute the hit ratio for a program that loops 4 times from locations 0 to 42 (base 10) in memory. c) Compute the effective access time for this program.

A direct-mapped cache consists of 16 blocks. A byte-addressable main memory contains 4K blocks of 16 bytes each. Access time for the cache is 30 ns and the time required to fill a cache slot from main memory is 250 ns. Assume a request is always started in sequential to cache and then to main memory. If a block is missing from cache, the entire block is brought into the cache and the access is restarted. Initially, the cache is empty. a) Show the main memory address format that allows us to map addresses from main memory to cache. Be sure to include the fields as well as their sizes. b) Compute the hit ratio for a program that loops 4 times from locations 0 to 42 (base 10) in memory. c) Compute the effective access time for this program.

Systems Architecture

7th Edition

ISBN:9781305080195

Author:Stephen D. Burd

Publisher:Stephen D. Burd

Chapter11: Operating Systems

Section: Chapter Questions

Problem 2VE

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A direct-mapped cache consists of 8 blocks. A byte-addressable main memory contains 4K blocks of eight bytes each. Access time for the cache is 20 ns and the time required to fill a cache slot from main memory is 300 ns. Assume a request is always started in sequential to cache and then to main memory. If a block is missing from cache, the entire block is brought into the cache and the access is restarted. Initially, the cache is empty. c) Compute the effective access time for this program. Show me how to solve using this equation: EAT = H x AccessC + (1 – H) x AccessMM where H is the cache hit rate and AccessC and AccessMM are the access times for cache and main memory, respectively. thanks
A computer of 32 bits has a cache memory of 64 KB with a cache line size of 64 bytes. The cache access time is 20 ns, and the miss penalty is 120 ns. The cache is 2-way associative. a) What is the number of cache lines? b) What is the number of cache sets? c) What is the number of lines per set? d) Draw a scheme of this cache. e) Calculate the time to read a word in case of miss.
This function will be able to look at which fields in a log entry that it needs to. When you use 64-byte cache blocks and don't prefetch, the following code calculates the average number of cache misses for each entry in the cache.
A cache is set up with a block size of 32 words. There are 64 blocks in cache and set up to be 4-way set associative. You have byte address 0x8923. Show the word address, block address, tag, and index Show each access being filled in with a note of hit or miss. You are given word address and the access are: 0xff, 0x08, 0x22, 0x00, 0x39, 0xF3, 0x07, 0xc0.
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3. The series of memory address references given as word addresses are 122, 126, 126, 126, 116, 300, 116, and 118. Assume a direct-mapped cache with eight one-word blocks that is initially empty. Label each reference in the list as a hit or miss and show the contents of the cache with figure after each reference.
A direct-mapped cache consists of eight blocks. A byte-addressable main memory contains 4K blocks of eight bytes each. Access time for the cache is 20 ns and the time required to fill a cache slot from main memory is 200 ns. Assume a request is always started in sequential to cache and then to main memory. If a block is missing from cache, the entire block is brought into the cache and the access is restarted. Initially, the cache is empty. Show the main memory address format that allows us to map addresses from main memory to cache. Be sure to include the fields as well as their sizes. Compute the hit ratio for a program that loops 3 times from locations 0 to 65 (base 10) in memory. Compute the effective access time for this program.
This function will be able to determine the fields in a log entry it needs to look at in order to do its job properly. The following line of code computes the average number of cache misses for each item in the cache when 64-byte cache blocks are used without any prefetching being performed by the program.
In the event that a request cannot be fulfilled by the cache, the processor will submit a request to main memory while the write buffer delivers the relevant data block. What steps need to be taken here?
Suppose a computer using direct mapped cache has 232 byte of byte-addressable main memory, and a cache of 1024 blocks, where each cache block contains 32 bytes. a) How many blocks of main memory are there? b) What is the format of a memory address as seen by the cache, i.e., what are the sizes of the tag, block, and offset fields? c) To which cache block will the memory address 0x000063FA map?
A 2-way set associative cache consists of four sets. Main memory contains 2K blocks of eight words each. Show the main memory address format that allows us to map addresses from main memory to cache. Be sure to include the fields as well as their sizes. Compute the hit ratio for a program that loops 6 times from locations 8 to 51 in main memory. You may leave the hit ratio in terms of a fraction. Please show details how you obtain the result.
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