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Questions tagged [hyperthreading]

In a hyperthreaded CPU, for each processor core that is physically present, the operating system addresses two virtual or logical cores, and shares the workload between them when possible.

In an hyper threaded environment, For each processor core that is physically present, the operating system addresses two virtual or logical cores, and shares the workload between them when possible.

This allows to decrease the number of dependent instructions on the pipeline. It takes advantage of superscalar architecture (multiple instructions operating on separate data in parallel).

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Single Windows process cannot use all of the 80 available threads of my setup, why?

I have both Linux and Windows 10 installed on a dual Xeon 6138 computer with 64GB of RAM. I cannot access the computer immediately (because of the lockdown) but I strongly believe the Windows version is Windows 10 Enterprise. The system has last…
Martin Frank
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threads and intel's (and AMD's) product descriptions

Many years ago ago I created many-threaded code on one-kernel processors. I don't remember if it was Posix' PThreads. Can someone please clarify what Intel/AMD means when they say "4 cores 4 threads (if HT - or SMT - not activeated)"? I should be…
nero_pelleman
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Disabling Hyperthreading on Nodes in an AWS EC2 Cluster through Ray Configuration

I have a task running on an EC2 cluster which starts to slow down progressively as virtual CPUs are employed (regardless of EBS volume size). To avoid this I want to disable hyperthreading on all nodes and was trying to implement the advice given…
Nick Mint
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How to optimize code for Simultaneous Multithreading?

Currently, I am learning parallel processing using CPU, which is a well-covered topic with plenty of tutorials and books. However, I could not find a single tutorial or resource that talks about programming techniques for hyper threaded CPU. Not a…
Duke Le
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Indy Sockets gradually slows down on hyper threaded machines

This is a long shot but maybe someone has an idea. I am using IndySockets, a library that extends .Net sockets classes in a multithreaded (20-25 threads) web crawling application. The app is run on a number of different servers, some of which have…
Brian
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Weight-factor to determine Virtual Cores for a Virtual Machine

I have to design an algorithm which will decide to assign virtual cores to a VM. e.g. I have 2 options to create a machines. That could be physical/virtual. Let's consider 2 cases: If I require 1-core of 2.3 GHz, which means I require a processor…
Asif Mehmood
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Do I need to re-deploy my cpu pinned VMs after enabling hyper-threading?

I have openstack running and kvm VMs are scheduled with cpu pinning. I have some requirement to enable hyper-threading but will this require redeploying the VMs due to the fact that the cores count and numbering will change?
Bishoy Mushraky
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Using hyper threading to buffer reading a file

If I'm trying to read through a file using a Java BufferedReader. Would it be faster to use multihreading to get the next piece of the buffer into Ram while I'm doing operations on the previous piece of the buffer? I know reading is especially slow…
hackerman9000
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What's the reason of the strange experiment result?

I have a problem with experiment on my computer. I've done 300 tests of parallel algorithm (32 threads) and seen, that runtime of about 10% tests is less than others. It looks like that: we have 100 tests with runtime of each about 100 ms, then we…
Luba Philippova
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What's the reason of strange experiment results?

I have a problem with experiment on my computer. I've done 300 tests of parallel algorithm (32 threads) and seen, that runtime of about 10% tests is less than others. It looks like that: we have 100 tests with runtime of each about 100 ms, then we…
Luba Philippova
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Does hyper threading change the binary machine code of a compiled program?

Does hyper threading change the binary code sequence of a compiled program? If we had a compiled binary code of say: 10100011100011100101010010011111100011111110010111 If hyper threading were enabled, what would a thread represent? Would it be just…
user10713170
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How to monitor contention from competing hyperthreads

Is there some performance counter or similar available which can help quantify the extent to which two hyperthreads on the same core are competing with each other for execution resources? Use case: in a shared infrastructure environment like…
Phil Frost
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Physical core and Logical cores on different cpu AMD/Intel

Can anyone confirm that for example Intel i3 CPU has 2 physical cores and 4 logical cores, so if I set Process affinity to Core #0 so that means I set on first physical cores 1 logical core, but if I set on Core #1 so it means I set on first…
JonZ
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Hyperthreading: There are not enough slots available

I tried to assign 4 tasks to 4 processors. Output of hwloc-ls --of console is: L2 L#0 (256KB) + L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 PU L#0 (P#0) PU L#1 (P#2) L2 L#1 (256KB) + L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 PU L#2…
Shibli
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Hyperthreading on/off in simple python script

I read something about hyperthreading and found out how beneficial it is for performace. I know the idea is something like when 2 disjoint processes on core are going to execute, in hyperthreading it can be executed in the same time. I also know,…
Juraj Karlubík
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