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Questions tagged [hyperthreading]

55 questions
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Is it possible to tell which cpus are hyperthreads of the same core?

I have a server that is a quad-core i-7 with hyperthreading enabled. The kernel recognises this as 8 cpus, as it should. I want to create a couple virtual hosts running on this machine. virt-manager lets me select which cpus are used on which…
Exodist
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Turning off HyperThread by BIOS or kernel?

Is there any performance difference between these disabled HyperThread scenarios? Which is the best, and why? Disable HT in BIOS Use noht kernel parameter The high-optimized parallel applications works slower with enabled…
andras.tim
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Will multiple processors show in /proc/cpuinfo on a kernel that doesn't have SMP enabled?

I have recently migrated an application from one server to another and am having some issues I am wondering if they are associated to HyperThreading. In regards to my question, I currently don't have access to the old box. When I did, I know that…
ManiacZX
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VMWare ESXi and Hyperthreading

I have (as some are probably tired of seeing on SF) a Dell 2950, dual 4 core 3Ghz processors running ESXi. I noticed on the VSphere management console that the server says it doesn't have hyperthreading enabled ("inactive") Apparently it is by…
Bart Silverstrim
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KVM: Which CPU for VM ('host' vs 'kvm64') to use for web load?

Playing with Proxmox 5.0 as a hypervisor platform and set up KVM VM to serve website, I really wonder if I should use kvm64 "virtual" CPU or try to use host. To be specific, I have an 4-core CPU that's capable of hyper-threading which results in 8…
Alexander
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Linux Load Averages and HyperThreads

My rough understanding of a Linux load Average is that for every integer a CPU core is working all the time. For example, 1 means on a 4 core system that 1 core is working at capacity. How does HyperThreading factor into this? Is it even considered…
Jacob
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Hyperthreading vs. SQL Server & PostgreSQL

I have read that hyperthreading is a "performance killer" when it comes to DBs. However, what I read didn't state which CPUs. Further, it mostly indicated that I/O was "cut to < 10% performance". That logically doesn't make sense since I/O is…
IamIC
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Hyper-V processors

I'm running a HP ProLiant DL380G6 with 2x Intel® Xeon® E5520 Quad Core Processor 2.26 GHz and 12GB of ram. I got Hyper-V installed and 3 VMs for now. If I open up task manager I can see 16 cores (I'm guessing that's 8 cores + 8 because of…
Acanthus
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SQL 2005 Standard Questions

I have a question about the tempdb files and hyperthreading. Here are the sw/hw specs. Server 2008 SP2 Standard X64 SQL 2005 Standard Sp3 x64 Dual Quad Core Xeon's E5540's (HT enabled) 12 GB Ram My first question is how many tempdb files should I…
Harris
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How to make Windows 2008 R2 see 4 CPU cores, with two single core processors , Hyperthreading enabled

I had server with old Xeon DP and Windows 2008 R2 , With hyperthreading enabled OS saw 2 CPU cores. Recently I've added second same Xeon DP , but OS steel sees 2 CPU cores. I did uninstall all cpu's as in Microsoft KB (tried reinstall also). The…
SalimQrdl
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Hyper-Threading & htop/system-monitor

I'm running a large set of simulations on a quad-core Xenon E5520 with Hyper-Threading enabled. My software automatically detects 8 (virtual) cores and launches 8 simulations to run in parallel. However htop and system-monitor only show each of the…
Emily
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Should I expect a great increase in Oracle performance in terms of handling multiple requests switching from single to dual core?

We have an Oracle database of roughly 100 GB that runs on top of a Windows Server 2k3R2 VM in ESX in a 1 socket, 1 core configuration. Whenever it has to handle a major query it seems to get "pegged" for the duration of that query (50% - 75% CPU…
tacos_tacos_tacos
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CPU Resource pool with and without hyperthreading in vmware esx/esxi

VMWare ESX/ESXI running with AMD 12core @2.2GHz. Intel 6core @2.4GHz In resource pool, with amd cpu I should see 26.4GHz available. Now it's interesting what will be shown with Intel CPU? Am I gonna get 14.4GHz resource pool or 28.8GHz?
jM2.me
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Optimal number of threads for compute-intensive task on server with Hyperthreading

When running a compute-intensive task on a server with an Intel i7 quad-core processor with Hyperthreading, is it ideal to run eight threads (for the eight virtual cores), or only four (for the four physical cores)? Each thread achieves consistent…
Will Johnson
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Why would only half of the cores on my hyperthreaded linux server be loaded?

I have a server which is a 12 core hyperthreaded system, which means I have 24 virtual cores. I'm running 24 processes on my server, each listening on its own port and doing the same things, albeit from different clients and different requests. The…
papercrane
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