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Recent questions tagged translation-lookaside-buffer

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GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 46
Assume that for a given system, virtual addresses are $40$ bits long and physical addresses are $30$ bits long. The page size is $8$ KB. The Translation Look-aside Buffer (TLB) in the address translation path has $128$ entries. At most ... distinct virtual addresses can be translated without any TLB miss? $2^7$ $2^{20}$ $2^{13}$ $2^8$

GO Classes asked in Operating System Jan 28

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1 answer

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Madeeasy workbook, chapter: Memory management
Consider a k-level paging system along with a TLB. A TLB takes 10ns, and a memory takes 100ns on average. The hit ratio of TLB is equal to 0.8. If it is known that the average memory access time is 70ns, then the value of k is?

Gaurav Padole asked in Operating System Dec 29, 2022

by Gaurav Padole

661 views

1 vote

1 answer

3

DRDO CSE 2022 Paper 2 | Question: 9
Assume that in a certain computer, the virtual addresses are $64$-bit long, the physical addresses are $48$-bit long, and the memory is word-addressable. The page size is $16 \mathrm{KB}$ and the word size is $8 \mathrm{B}$. ... transalation path has $256$ valid entries. At most how many distinct virtual addresses can be translated without any $\text{TLB}$ miss?

admin asked in Operating System Dec 15, 2022

by admin

356 views

23 votes

2 answers

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GATE CSE 2022 | Question: 28
Which one of the following statements is $\text{FALSE}?$ The $\text{TLB}$ performs an associative search in parallel on all its valid entries using page number of incoming virtual address. If the virtual address of a word given by $\text{CPU}$ has a ... $\text{V2}$ map to the same value while hashing, then the memory access time of these addresses will not be the same.

Arjun asked in Operating System Feb 15, 2022

by Arjun

7.9k views

2 votes

3 answers

5

Applied Test Series
A computer system has a page size of 1024 bytes and maintains the page table for each process in main memory. The overhead required for doing a lookup in the page table is 500 ns. To reduce this overhead, the computer has a TLB that ... frame mappings. A TLB lookup requires 100ns. Which TLB hit-rate will ensure an average virtual address translation time of exactly 200ns?

LRU asked in Operating System Jan 11, 2022

by LRU

808 views

0 votes

1 answer

6

Applied Live Test
Given a byte addressable system which implements demand paging, a TLB has 64 entries and the frame size is 4KB. The LAS is 4MB. TLB has a hit ratio of 90% and has an access time of 2 ns. If the main memory access time is 100 ns and page fault is 5%. The page fault service time is given to be 100 ms. The TLB reach for this system given above is _____ B Anyone can help this.

ramakrushna asked in Operating System Jan 3, 2022

504 views

1 vote

1 answer

7

Applied Practice test
Suppose: TLB lookup time = 20 ns TLB hit ratio = 80% Memory access time = 75 ns PFST = 500,000 ns 50% of the pages are dirty OS uses a single level page table What is the approximated effective access time (EAT) if we assume the page fault rate is 10%? Assume the cost to update the TLB, the page table, and the frame table (if needed) is negligible.

darshak_devani asked in Operating System Oct 18, 2021

by darshak_devani

815 views

2 votes

2 answers

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UGC NET CSE | October 2020 | Part 2 | Question: 18
Consider a single-level page table system, with the page table stored in the memory. If the hit rate to TLB is $80\%$, and it takes $15$ nanoseconds to search the $TLB$, and $150$ nanoseconds to access the main memory, then what is the effective memory access time, in nanoseconds? $185$ $195$ $205$ $175$

go_editor asked in Operating System Nov 20, 2020

2.1k views

2 votes

2 answers

9

NIELIT 2017 July Scientist B (CS) - Section B: 32
A CPU generates $32$-bit virtual addresses. The page size is $4$ KB. The processor has a Translation Look-aside Buffer (TLB) which can hold a total of $128$ page table entries and is $4$-way set associative. The minimum size of the TLB tag is $\text{11 bits}$ $\text{13 bits}$ $\text{15 bits}$ $\text{20 bits}$

admin asked in Operating System Mar 30, 2020

by admin

1.2k views

0 votes

0 answers

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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 55 (Page No. 261 - 262)
Write a program that can be used to compare the effectiveness of adding a tag field to $TLB$ entries when control is toggled between two programs. The tag field is used to effectively label each entry with the ... for a simple (but nontrivial) input example. Plot the number of $TLB$ updates per $1000$ references.

admin asked in Operating System Oct 26, 2019

by admin

355 views

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0 answers

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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 53 (Page No. 261)
Write a program that demonstrates the effect of $TLB$ misses on the effective memory access time by measuring the per-access time it takes to stride through a large array. Explain the main concepts behind the ... but for an older computer with a different architecture and explain any major differences in the output.

admin asked in Operating System Oct 26, 2019

by admin

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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 23 (Page No. 256)
How can the associative memory device needed for a $TLB$ be implemented in hardware, and what are the implications of such a design for expandability?

admin asked in Operating System Oct 26, 2019

by admin

274 views

1 vote

1 answer

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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 22 (Page No. 256)
A computer whose processes have $1024$ pages in their address spaces keeps its page tables in memory. The overhead required for reading a word from the page table is $5\: nsec.$ To reduce this overhead, the computer has a $TLB,$ ... a lookup in $1\: nsec.$ What hit rate is needed to reduce the mean overhead to $2\: nsec?$

admin asked in Operating System Oct 26, 2019

by admin

770 views

1 vote

2 answers

14

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 16 (Page No. 255)
You are given the following data about a virtual memory system: The $TLB$ can hold $1024$ entries and can be accessed in $1$ clock cycle $(1\: nsec).$ A page table entry can be found in $100$ ... $0.01\%$ lead to a page fault, what is the effective address-translation time?

admin asked in Operating System Oct 26, 2019

by admin

631 views

1 vote

1 answer

15

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 11 (Page No. 255)
Consider the following C program: int X[N]; int step = M; /* M is some predefined constant */ for (int i = 0; i < N; i += step) X[i] = X[i] + 1; If this program is run on a machine with ... for every execution of the inner loop? Would your answer in part $(a)$ be different if the loop were repeated many times? Explain.

admin asked in Operating System Oct 26, 2019

by admin

556 views

0 votes

1 answer

16

Self Doubt : Regarding TLB entry for a page not present in memory
If a page is not present in the memory, then its corresponding entry in the page table would have the ‘Present’ bit set as 0 to indicate , the page is not present. Will this entry be considered for caching in TLB? As I understand from above line in Tanenbaum, The entry should not be present in TLB. Is my understanding right?

Mayank0343 asked in Operating System May 8, 2019

543 views

1 vote

1 answer

17

ISI2017-PCB-CS-5(b)
Consider a paging system with the page table stored in memory. If a memory reference takes $200$ nanoseconds, how long does a paged memory reference take? If we add a Translation Lookaside Buffer (TLB) and $75$ percent of all page-table references are ... memory reference time? Assume that finding a page-table entry in the TLB takes $20$ nanoseconds, if the entry is present.

akash.dinkar12 asked in Operating System Apr 8, 2019

by akash.dinkar12

7.8k views

0 votes

1 answer

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Galvin Edition 9 Exercise 9 Question 15 (Page No. 452)
A simplified view of thread states is $Ready$, $Running$, and $Blocked$,where a thread is either ready and waiting to be scheduled, is running on the processor, or is blocked (for example, waiting for I/O). This is illustrated ... the thread change state if an address reference is resolved in the page table? If so, to what state will it change?

akash.dinkar12 asked in Operating System Mar 21, 2019

by akash.dinkar12

522 views

0 votes

1 answer

19

Galvin Edition 9 Exercise 9 Question 14 (Page No. 452)
Assume that a program has just referenced an address in virtual memory. Describe a scenario in which each of the following can occur. (If no such scenario can occur, explain why.) • $TLB$ miss with no page fault • $TLB$ miss and page fault • $TLB$ hit and no page fault • $TLB$ hit and page fault

akash.dinkar12 asked in Operating System Mar 21, 2019

by akash.dinkar12

2.4k views

1 vote

0 answers

20

Caching
Given the following information: TLB hit rate 95%, TLB access time is 1 cycle. cache hit rate 90 %, cache access time is 1 cycle. When TLB and cache both get miss; page fault rate is 1% The TLB access and acache access are ... cycles Access to hard drive requires 50,000 cycles. Compute the average memory access latencies when the cache is physically addresses (in cycles).

s_dr_13 asked in CO and Architecture Mar 10, 2019

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21

effective memory access time
A demand paging uses a TLB and a single level page table stored in main memory. The memory access time is 5s. The page fault service time is 25s. If 70% of access is in TLB and of the remaining, 20% is not present in the main memory. The effective memory access time is? Thanks!

Abhipsa asked in Operating System Jan 27, 2019

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0 answers

22

TLB misses
1 2 2048 none

gate_forum asked in Operating System Jan 13, 2019

278 views

2 votes

1 answer

23

TLB hit ration and memory lookup time
Consider a system where TLB lookup time is $25$ ns and memory access time is $200$ ns, respectively. Assuming a virtual address space of $2$ KB, page size of $32$ bytes, and a PTE size of $2$ bytes, what is the minimum TLB hit ratio that results in an average v2p (virtual to physical) translation latency of $185$ ns?

dd asked in Operating System Jan 13, 2019

by dd

751 views

0 votes

1 answer

24

me test series
A computer system implements a 38 bit virtual address, page size of 16 KB, and 256 entries translation look aside buffer (TLB) organized into 32 sets each having 8 ways. If TLB tag does not store any process id. The minimum length of TLB tag in bits is____

newdreamz a1-z0 asked in Operating System Jan 11, 2019

by newdreamz a1-z0

499 views

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0 answers

25

UPPCL AE 2018:57
Consider the following $\text{C}$ function executed in an $\text{OS}$ with paging where the page size is $4$ kilobytes. Further, assume that the system employs a $32-$ entry direct mapped $\text{TLB}$ int *alloc_and_init() { int counter, value = 0, size = 2048; int ... of the program, what is the number of $\text{TLB}$ misses during the execution of the for loop? $2048$ $2$ $0$ $1$

admin asked in Operating System Jan 5, 2019

by admin

247 views

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Recent questions tagged translation-lookaside-buffer