Consider a demand-paging system in which the replacement of a page takes 20 milliseconds (access time and data transfer). Addresses are translated through a page table in main memory, with an access time of 1 microsecond per memory access. Thus, each memory reference through the page table takes two accesses.
To improve this time, a TLB is added to the system to reduces access time to one memory reference, if the page-table entry is in the associative memory.
Assume that 80 percent of the accesses are in the associative memory and that, of the remaining, 20 percent (or 4 percent of the total) cause page faults. What is the effective memory access time?
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Consider a demand-paging system in which the replacement of a page takes 20 milliseconds (access time...
Consider a demand-paging system with a paging disk that has an average access and transfer time of 20 milliseconds. Addresses are translated through a page table in main memory, with an access time of 1 microsecond per memory access. Thus, each memory reference through the page table takes two accesses. To improve this time, we have added an associative memory that reduces access time to one memory reference, if the page-table entry is in the associative memory. Assume that 80...
Question # 3 Consider a demand-paged system where the page table for each process resides in main memory. In addition, there is a fast associative memory (also known as TLB which stands for Translation Look-aside Buffer) to speed up the translation process. Each single memory access takes 1 microsecond while each TLB access takes 0.2 microseconds. Assume that 2% of the page requests lead to page faults, while 98% are hits. On the average, page fault time is 20 milliseconds...
3. Consider a paging system with the page table in memory. A. If a memory reference takes 100 nanoseconds, how long does a paged memory reference take? B. If we add TLBs, and 75 percent of all page-table references are found in the TLBs, what is the effective memory reference time? (Assume that finding a page-table entry for the TLBs takes 20 nanoseconds.) C. It takes 750 milliseconds to service a page fault. The page fault rate is .001. What...
3. Consider a paging system with the page table in memory. A. If a memory reference takes 100 nanoseconds, how long does a paged memory reference take? B. If we add TLBs, and 75 percent of all page-table references are found in the TLBs, what is the effective memory reference time? (Assume that finding a page-table entry for the TLBs takes 20 nanoseconds.) C. It takes 750 milliseconds to service a page fault. The page fault rate is .001. What...
Problem 3 (25 points): Consider a paging system with the page table stored in memory. Ifa memory reference takes 200 nanoseconds, how long does a paged memory reference take? If we add associative registers, and 75 percent of all page-table references are found in the associative registers, what is the effective memory reference time? (Assume that finding a page-table entry in the associative registers takes zero time if the entry is there.) a. b.
7 pts Question 30 Consider a computer system that uses virtual memory with paging with a TLB. Suppose main memory access time is 10 ns and the time to look up the TLB 1 ns. Assume no page faults and the TLB has a hit of 95%. What is the effective memory access time (express in ns) 11ns
Answer the following questions a) If average page-fault service time is 9 milliseconds, a memory access time is 202 nanoseconds, and the page fault rate is 0.2% then what is the effective access time (in nanoseconds) for a demand paging scheme. b) Under what circumstances do page faults occur? Describe the actions taken by the operating system when a page fault occurs.
Question 30 7 pts Consider a computer system that uses virtual memory with paging with a TUB. Suppose main memory access time is 10 ns and the time to look up the TLB 1 ns. Assume no page faults and the TLB has a hit of 95%. What is the effective memory access time (express in ns)
Consider the following system: Byte addressable 16-bit addresses 256B pages Single level Page Table System The system utilizes a fully-associative TLB with 4 entries and an LRU replacement policy. Given the access pattern and timings below, complete the following table. Assume the TLB begins initially empty and the cache is physically addressed NOTE: Access times are not inclusive and components are accessed sequentially. Time to update the TLB is negligible, everything else that needs to be updated will require a...
Q5. Consider a memory system where all pages fit in memory. The TLB takes 15 nanoseconds to access and memory takes 120 nanoseconds to access. What is the effective access time for 1 level paging if the hit rate is 65%? What if it’s 95%? What is the effective access time if not all processes fit into memory and the swap time is 850,000 nanoseconds for a page fault?