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Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?
- a)13.0
- b)12.8
- c)12.6
- d)12.4
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Consider a system with 2 level cache. Access times of Level 1 cache, L...
By default we consider hierarchical access - because that is the common implementation and simultaneous access cache has great practical difficulty. But here the question is a bit ambiguous -- it says to ignore search time within the cache - usually search is applicable for an associative cache but here no such information given. So, may be they are telling to
ignore the search time for L1 and just consider the time for L2 for an L1 miss and similarly just consider memory access time for L2 miss. This is nothing but simultaneous access.
Access time for hierarchical access
ignore the search time for L1 and just consider the time for L2 for an L1 miss and similarly just consider memory access time for L2 miss. This is nothing but simultaneous access.
Access time for hierarchical access
Access time for simultaneous access
Both options in choice - :OMost Upvoted Answer
Consider a system with 2 level cache. Access times of Level 1 cache, L...
Given information:
- Level 1 cache access time: 1 ns
- Level 2 cache access time: 10 ns
- Main memory access time: 500 ns
- Level 1 cache hit rate: 0.8
- Level 2 cache hit rate: 0.9
Calculating average access time:
To calculate the average access time, we need to consider the hit rate at each level of the cache.
1. Level 1 cache:
- The hit rate at Level 1 cache is 0.8, so the access time when a cache hit occurs is 1 ns.
- The miss rate at Level 1 cache is 1 - 0.8 = 0.2, so the access time when a cache miss occurs is the sum of the access time at Level 2 cache and the access time at main memory.
- The access time at Level 2 cache is 10 ns.
- The access time at main memory is 500 ns.
2. Level 2 cache:
- The hit rate at Level 2 cache is 0.9, so the access time when a cache hit occurs is the access time at Level 1 cache (1 ns) plus the access time at Level 2 cache (10 ns), which is 11 ns.
- The miss rate at Level 2 cache is 1 - 0.9 = 0.1, so the access time when a cache miss occurs is the sum of the access time at main memory (500 ns) and the access time at Level 2 cache (10 ns), which is 510 ns.
3. Average access time:
To calculate the average access time, we need to consider the hit rate at each level of the cache and the access time when a cache hit or miss occurs.
The average access time can be calculated using the formula:
Average access time = (Hit rate * Access time on hit) + (Miss rate * Access time on miss)
For the given system:
Average access time at Level 1 cache = (0.8 * 1 ns) + (0.2 * 510 ns) = 102.2 ns
Average access time at Level 2 cache = (0.9 * 11 ns) + (0.1 * 510 ns) = 65.1 ns
Average access time of the system = (0.8 * 102.2 ns) + (0.2 * 65.1 ns) = 12.6 ns
Therefore, the average access time of the system is 12.6 ns (option C).
- Level 1 cache access time: 1 ns
- Level 2 cache access time: 10 ns
- Main memory access time: 500 ns
- Level 1 cache hit rate: 0.8
- Level 2 cache hit rate: 0.9
Calculating average access time:
To calculate the average access time, we need to consider the hit rate at each level of the cache.
1. Level 1 cache:
- The hit rate at Level 1 cache is 0.8, so the access time when a cache hit occurs is 1 ns.
- The miss rate at Level 1 cache is 1 - 0.8 = 0.2, so the access time when a cache miss occurs is the sum of the access time at Level 2 cache and the access time at main memory.
- The access time at Level 2 cache is 10 ns.
- The access time at main memory is 500 ns.
2. Level 2 cache:
- The hit rate at Level 2 cache is 0.9, so the access time when a cache hit occurs is the access time at Level 1 cache (1 ns) plus the access time at Level 2 cache (10 ns), which is 11 ns.
- The miss rate at Level 2 cache is 1 - 0.9 = 0.1, so the access time when a cache miss occurs is the sum of the access time at main memory (500 ns) and the access time at Level 2 cache (10 ns), which is 510 ns.
3. Average access time:
To calculate the average access time, we need to consider the hit rate at each level of the cache and the access time when a cache hit or miss occurs.
The average access time can be calculated using the formula:
Average access time = (Hit rate * Access time on hit) + (Miss rate * Access time on miss)
For the given system:
Average access time at Level 1 cache = (0.8 * 1 ns) + (0.2 * 510 ns) = 102.2 ns
Average access time at Level 2 cache = (0.9 * 11 ns) + (0.1 * 510 ns) = 65.1 ns
Average access time of the system = (0.8 * 102.2 ns) + (0.2 * 65.1 ns) = 12.6 ns
Therefore, the average access time of the system is 12.6 ns (option C).
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Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer?
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Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? for Computer Science Engineering (CSE) 2025 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer?.
Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? for Computer Science Engineering (CSE) 2025 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer?.
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Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer?, a detailed solution for Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? has been provided alongside types of Consider a system with 2 level cache. Access times of Level 1 cache, Level 2 cache and main memory are 1 ns, 10 ns, and500 ns, respectively. The hit rates of Level 1 and Level 2 caches are 0.8 and 0.9, respectively. What is the average accesstime of the system ignoring the search time within the cache?a)13.0b)12.8c)12.6d)12.4Correct answer is option 'C'. Can you explain this answer? theory, EduRev gives you an
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