Questions tagged [tlb]
The translation lookaside buffer (TLB) enables modern CPUs to quickly map virtual memory addresses to physical memory addresses and vice versa. Operations that flush the TLB cause a performance hit until it is repopulated.
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Are TLB and Cache Accesses Always Done in Series?
Since programs use virtual addresses and the cache operates on only physical addresses, does the a TLB(and potential page table access) have to happen before accessing the physical cache? If not, how ...
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How can fragmented physical memory cause TLB thrashing?
I read this passage on https://en.wikipedia.org/wiki/Fragmentation_(computing) : "However, if the working set is fragmented, then it will not fit into 64 pages, and execution will slow due to ...
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Determine TLB size on ARM64 (Linux)
For Intel there's cpuid command that can report TLB levels, sizes, associativity, etc. Is there a way to do the same on ARM64?
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AT (Address Translation) instruction's privilege level in ARMv8
Executing AT instruction (Address Translation) from user-space (a.k.a EL0) gives SIGILL, so I tried executing it from kernel-space (EL1), this way it didn't fail.
I also found that AT is alias for SYS ...
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TLB flush during context switch
I am investigating the effects of context switch on linux x86 machines. In particular, I am interested in TLB.
My understanding, after reading Intel Manual 3A (section 4.10.4 "Invalidation of ...
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Does malloc consider TLB hits?
I recently tried to examine how malloc() and free() populate the address space with differently sized chunks of memory on my system. It is a debian linux with the glibc malloc implementation and 4 GB ...
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os161: TLB miss for getpidtest
Im trying to test my getpid.c from os161 and it gives this error, i know its because it is trying to access some invalid pointer but it does not make any sense. I tried gdb and i cant really use it ...
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How to remove the prefix auto added for C# enum when generate tlb
I have a C# dll which are COM visible.
public class Class1
{
public enum enumTest
{
None = 0,
enumA = 1,
enumB = 2,
enumC = 3
}
}
When use oleview.exe to ...
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In x86_64 architecture, if I modify a PTE in the page table, when will it be sync to TLB?
I am designing an optimistic concurrency control mechanism to address TLB shootdowns for a specific application. The approach operates on the following principles:
The application manages data at the ...
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Troubleshooting ARM Cortex-A72 Address Translation: Seeking Clarification on Level 1 vs. Level 2 Translation and Register Analysis
I'm using an ARM Cortex-A72 processor running a custom real-time operating system. I'm trying to understand how address translation is performed, but there are some points I couldn't grasp fully.
I ...
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How does a TLB manage memory translation for addresses that cross page boundaries?
Let's say we have a page size of 4096 Bytes, and we have two contiguous virtual memory pages mapped to discontinuous physical pages, i.e
[x , x + 4096 * 2] - Maps to -> [A, A + 4096], [B, B + 4096]
...
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size of TLB entry
Problem
What is the size of a TLB (translation lookaside buffer) entry in bits?
Reference
I use the definition/setup of a translation lookaside buffer from the book
Computer Systems: A Programmer's ...
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What's the purpose of ref bit in TLB
From Computer Organization and Design, the concept of TLB is designed as the following
https://i.sstatic.net/0p3ZH.png
I understand that the ref bit should be used to indicate if a page has been ...
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Why does it take so long for cpu to write memory after it has obtained the physical address?
https://github.com/torvalds/linux/commit/6ce64428d62026a10cb5d80138ff2f90cc21d367:
cpu0 cpu1 cpu2
---- ---- ----
[ ...
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Will page table data be saved in the CPU cache? [duplicate]
The page table will be saved in memory and accessed during the page walk process after TLB miss. Will this portion of memory be treated as ordinary data and enter the traditional L1-D/L2/L3 cache?
If ...
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