tlb Questions

11

Solved

I am reading Operating Systems Concept and I am on the 8th chapter! However I could use some clarification, or reassurance that my understanding is correct. Logical Addresses: Logical addresses a...
Whensoever asked 13/9, 2010 at 3:43

3

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I am currently studying Operating Systems by A Silberschatz, P Galvin, G Gagne. I am studying memory management strategies, and on section where they introduce Translation Look-aside Buffer (TLB). ...
Psychomotor asked 9/10, 2018 at 5:32

1

I have a discrete NVIDIA GPU (say, Kepler or Maxwell). I want to clear my L2 cache before some kernel is scheduled, so as not to taint my test results. I could do something like allocate a large s...
Instill asked 15/7, 2015 at 11:39

1

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Since different processes have their own Page table, How does the TLB cache differentiate between two page tables? Or is the TLB flushed every time a different process gets CPU?
Spinner asked 1/12, 2021 at 15:59

4

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Just going off wikipedia: The page table, generally stored in main memory, keeps track of where the virtual pages are stored in the physical memory. This method uses two memory accesses (one for...
Saltus asked 15/12, 2016 at 20:53

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I have an application where I need about 850 MB of continuous memory and be accessing it in a random manner. I was suggested to allocate a huge page of 1 GB, so that it would always be in TLB. I've...
Jellied asked 2/9, 2020 at 12:10

1

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Is TLB hierarchy inclusive on modern x86 CPU (e.g. Skylake, or maybe other Lakes)? For example, prefetchtn brings data to the level cache n + 1 as well as a corresponding TLB entry in DTLB. Will i...
Cerous asked 12/4, 2020 at 20:11

5

Can someone clearly explain me the difference between a cache miss, a tlb miss and page fault, and how do these affect the effective memory access time?
Radu asked 15/6, 2016 at 3:59

2

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I'm exploring leaf 0x02 of the cpuid instruction and came up with a few questions. There is a table in the documentation which describes what cpuid results mean for the TLB configuration. Here they...
Pros asked 27/9, 2019 at 6:15

2

I'm a bit confused about what happens when we're in user-mode and a page fault occurs. IIRC, a page fault will be generated when the TLB is attempting to map my (user-space) virtual address into ...
Inviolable asked 3/5, 2019 at 4:12

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This scenario came into my head and it seems a bit basic but I'll ask. So there is a virtual index and physical tag in L1 but the set becomes full so it is evicted. How does the L1 controller get...
Cominform asked 27/3, 2019 at 23:9

1

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Is that TLB contains only entries for a single process? So the page table in the following line from wiki is belongs to certain process, which is maintained by operating system? The CPU's memory...
Confab asked 10/12, 2018 at 6:9

1

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According to some operating system textbooks, for faster context switches, people add ASID for each process in the TLB tag field, so we don't need to flush the entire TLB in a context switch. I ha...
Ferreira asked 15/10, 2018 at 9:7

1

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To my knowledge, both MMU and TLB are not shared in a hyper-threaded core in Intel x86_64. However, then, if two threads that don't share the address space are scheduled to the same physical core,...
Serow asked 16/7, 2018 at 11:31

2

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I read this SO question describing what a TLB shootdown is. I'm trying to understand if this is an operation performed by the kernel or by the processor or both? My questions are :- Does a TLB s...
Pinkard asked 9/5, 2018 at 15:14

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I have a test case to observe perf iTLB-loads,iTLB-load-misses by perf stat -e dTLB-loads,dTLB-load-misses,iTLB-loads,iTLB-load-misses -p 22479 and get the output : Performance counter stats f...
Pooka asked 20/4, 2018 at 3:8

1

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For Intel 64 and IA-32 processors, for both data and code independently, there may be both a 4KB TLB, and a Large Page (2MB, 1GB) TLB (LTLB). How does address translation work in this case? Would...
Platto asked 15/4, 2018 at 13:35

2

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for (int i = 0; i < 100000; ++i) { int *page = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); page[0] = 0; munmap(page, PAGE_SIZE); } I expect to get ...
Burks asked 31/1, 2018 at 22:16

3

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What is a TLB shootdown in SMPs? I am unable to find much information regarding this concept. Any good example would be very much appreciated.
Monocarpic asked 20/9, 2010 at 2:40

1

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I am not able to entirely grasp the concept of synonyms or aliasing in VIPT caches. Consider the address split as:- Here, suppose we have 2 pages with different VA's mapped to same physical addres...
Pentamerous asked 5/10, 2017 at 14:30

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I just want to clarify the concept and could find detail enough answers which can throw some light upon how everything actually works out in the hardware. Please provide any relevant details. In c...
Gan asked 29/9, 2017 at 0:16

2

My understanding is that hardware prefetching will never cross page boundaries. I'm wondering if a software prefetch has the same restriction i.e. can I use a software prefetch to avoid a future TL...
Fallal asked 8/2, 2013 at 22:12

2

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I can't understand the answer to this question: Consider an OS using one level of paging with TLB registers. If the page fault rate is 10% and dirty pages should be reloaded when needed, calculate...
Assault asked 7/1, 2013 at 8:58

6

This is a paragraph from Operating System Concepts, 9th edition by Silberschatz et al: The percentage of times that the page number of interest is found in the TLB is called the hit ratio. An 8...
Complicated asked 31/8, 2013 at 16:38

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The wiki webpage(https://en.wikipedia.org/wiki/Sandy_Bridge) mentioned that Data TLB has 64, 32 and 4 entries respectively for 4KB, 2MB and 1GB pages. I found these numbers hard to understand. San...
Illiberal asked 17/11, 2016 at 8:8

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