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Questions tagged [hyperthreading]

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Disable hyperthreading from within Linux (no access to BIOS)

I have a system running a financial trading application at a remote facility. I do not have access to the ILO/DRAC, but need to disable hyperthreading. The system runs Intel Westmere 3.33GHz X5680 hex-core CPUs. I can reboot, but want to make sure…
ewwhite
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Will disabling hyperthreading improve performance on our SQL Server install

Related to: Current wisdom on SQL Server and Hyperthreading Recently we upgraded our Windows 2008 R2 database server from an X5470 to a X5560. The theory is both CPUs have very similar performance, if anything the X5560 is slightly faster. However,…
Sam Saffron
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Hyper-V and Hyper-threading: On or off?

With the new Xeon CPUs supporting Hyper-threading, what is the current wisdom with regard to using it (or not) on a Hyper-V host machine? I was originally under the impression that turning it on in a virtual host environment could be detrimental as…
CapBBeard
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How many CPUs should be utilised with Hyperthreading?

Let's say I have a server cpu with 18 cores, with hyperthreading on, which means I can see 36 cpus in htop. To fully utilise the CPU and not impact single-thread performance, should I be aiming for all 36 "cores" to run at 100%, and the HT cores…
Tassadar
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Hyper Threading and Virtual Machines?

I already looked at this thread: Hyper-V and Hyper-threading: On or off?, but the only answer is Windows specific.... I am building a VM server (using Proxmox VE if that makes a difference) and was wondering about how hyper threading can affect…
Soviero
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Why did disabling hyperthreading make my server slower?

I have a server that's primarily running a Ruby script. Because Ruby (2.7) has a GIL, it is single threaded. My computer (server) has an Intel i3 dual core processor, but due to hyperthreading I see 4 cores. Ruby only utilizes 25% CPU under heavy…
S.Goswami
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Current wisdom on SQL Server and Hyperthreading?

Lots of articles out there (see Slava Oks's original SQL 2000 article and Kevin Kline's SQL 2005 update) recommend disabling hyperthreading on SQL servers, or at least testing your specific workload before enabling it on your servers. This issue is…
BradC
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taskset core numbers question

I have quad core CPU with hyper threading enabled. So I have 8 logical cores. I want to limit my application to use only 4 cores and I want this 4 cores to be different physical cores. Which taskset options (core numbers) should I use? : taskset -c…
Artem Bergkamp
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VMware / SQL - physical vs logical cores - how many vCPUs to assign when HT is enabled

We have a ESX host: It has 2 CPU x 8 cores each, and HT enabled. So, total 16 physical cores or 32 logical cores. It has a single dedicated SQL VM on it (no other VMs run on this host), and it has 16 vCPUs assigned: and the SQL NUMA config looks…
d-_-b
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VMware CPU Hyper Threading Scheduling Affinity

I have looked everyware and read a bunch of documentation on this but haven't found a direct answer so here it goes: There is a setting in the "Resources" Tab in vCenter that lets you configure Hyper-threading Core Sharing. I have this set to…
Mike Myers
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Enabled hyperthreading - causes qthread creation error on Ubuntu Precise 64 bit

We recently set up an HP ProLiant DL360p server for some heavy grunt-work. For one reason or another we disabled hyperthreading in the system BIOS when setting it up. Being a dual-CPU 8-core system, that gave us 16 hardware threads. 32 GB RAM. We…
davidA
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Nginx worker_processes and multi core cpu's - Do Hyper-threading cores count?

Quite often, when reading about the recommended worker_processes for nginx it is stated that this should be set to the numbers of cores the server hosting nginx has. We were wondering if we should count the number of HT cores for this as well? Or do…
anonymous-one
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EC2, Windows 10, half of the virtual processors

We run t3.large and m5.large instances, which have 2 vCPUs (as displayed in the EC2 management console). I'm trying to understand why the Windows 2019 (AMI provided by my IT) can only see half the number of logical CPUs. Half the number is reported…
fskexp
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CPU parking, windows 2012r2, with no hyper threading

I have server based on Intel R1304WT2GS with two e5-2660v3, windows 2012r2. I've installed last drivers from intel site. For business purposes i need to disable hyper threading, and use windows 8.1 / 2012r2. The problem is that all cores except two…
Dmitry
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AWS EC2 instance hyperthreading

I am currently doing some performance testing of web-apps that we have moved to AWS. One of the things we have noticed is that vCPU performance doesn't seem to be nearly as good as we'd expected. In fact, on a highly utilize single vCPU machine we…
zmcmahon
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