Questions tagged [smp]

Symmetric multiprocessing (SMP)

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Does the ZFS scrub support parallelization for increased performance, e.g., with a 64-core AMD Threadripper Pro?

I have a 24 drive zpool comprised of 3 RAIDZ1 vdevs running 8 Seagate Exos X18 16TB drives per vdev. This is on a Supermicro MB with a 64-Core (128 thread) AMD Threadripper Pro and 256GB ECC RAM. ...
docBrian's user avatar
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How to calculate the QuickPath Interconnect (QPI) bandwidth?

For Xeon E5-2697 v2, Intel lists: Bus Speed = 8 GT/s # of QPI Links = 2 According to Wikipedia, one must know the QPI frequency and link width to calculate the QPI bandwidth, but these don't seem to ...
MWB's user avatar
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How can I override IRQ affinity for NVME devices

I am trying to move all interrupts over to cores 0-3 to keep the rest of my cores free for high speed, low latency virtualization. I wrote a quick script to set IRQ affinity to 0-3: #!/bin/bash while ...
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Enabling Hyperthreading on a Centos 7.3 server using Intel Xeon E5620

I have a Centos 7.3 server running a dual socket quad core Intel Xeon CPU E5620 @ 2.40GHz. I would like to use hyperthreading on this server but it seems it has been disabled. The spec sheet for ...
Dave Smylie's user avatar
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What will happen if a CPU burst up to 100% utilization in an SMP infrastructure?

I have a web server that has 4 CPUs, It has somehow encountered packet loss intermittently. Finally we moved allthe application and data to another system that has 8 CPUs. We did this because we found ...
Jepsenwan 's user avatar
3 votes
1 answer
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Is a machine with a single NUMA node, actually a regular (non-NUMA) system?

First, let's check I got the fundamentals right: As I understand it, NUMA systems are a (asymmetric) network of NUMA nodes, where a NUMA node is usually (but not always) a physical CPU package. In a ...
Edd Barrett's user avatar
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NUMA processor definition

NUMA, non-uniform memory access designates a symetric multi-processing system where processors are grouped into nodes, with each group sharing some level of memory, so that memory access on same node ...
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Server crashes because of SMP

My web server is crashing every few days unless I disable SMP with "nosmp" parameter in Grub config. It is not an hardware failure because the problem persists after moving everything to a new machine....
Antares's user avatar
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SMP kernel sees only one CPU (i7-930) with ACPI enabled

A Gentoo box running a up-to-date SMP kernel sees only one CPU eventhough ACPI is enabled in AmiBIOS. Any ideas why? > uname -a Linux charlie 3.17.7-gentoo #1 SMP Mon Jan 12 19:31:07 CET 2015 ...
svoop's user avatar
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Host CPU use optimization on KVM

I've done KVM based virtualization setup with following configuration. HOST Machine ---------------- OS: CentOS 6.6 (64-bit) CPU: Intel(R) Xeon(R) CPU E5606 @ 2.13GHz RAM: 32 GBs Disk: 2 TBs (LVM-...
vasco.debian's user avatar
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Setting default_smp_affinity on Linux to the correct value

I have 12 core boxes: egrep -c processor /proc/cpuinfo 12 cat /proc/irq/default_smp_affinity fff I would like to use all of the cores so my understanding is that the default_smp_affinity should be ...
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4 answers
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Alternative system fans for EOL HP ML150 G6 servers

Background I have an HP ML150 G6 server that HP made 'End Of Life'. I added a second processor to the system but then was unable to get past POST due to a missing system fan. I found a diagram that ...
Morten Green Hermansen's user avatar
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Server crash : "unable to handle kernel paging request"

My fresh new Ubuntu webserver randomly crashes with the following error in the syslog. It doesn't respond anymore and I have to do a hard reboot. It happens almost one time a day. Server kernel is : ...
Antares's user avatar
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Enable SMP on Debian i386?

I've been running a couple old HP machines on Debian for a while, and only recently noticed that they were only 'recognizing' and using one processor. cat /proc/cpuinfo only shows output for processor ...
Libbux's user avatar
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Linux SMP Kernel Ram Utilization

I have a linux machine with Redhat 32 bit SMP Kernel installed , the ram size of machine is 16 GB and processor architecture is 64 bit. Please clarify my doubts on this setup : Can OS use the 16GB ...
Akhil Thayyil's user avatar
22 votes
4 answers
129k views

Execute curl requests in parallel in bash

What is the best way to execute 5 curl requests in parallel from a bash script? I can't run them in serial for performance reasons.
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How to change SMP affinity of an IRQ on Ubuntu PV domU inside Xen XCP?

I'd like to change IRQ SMP affinity for reasons, outlined in this question: CPU0 is swamped with eth1 interrupts But I can't — I see Input/output error when I try to write to /proc/irq/*/smp_affinity....
Alexander Gladysh's user avatar
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1 answer
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linux kernel soft lock nagios

I've had this happen a few times in the past few days, anyone have any idea what might be causing this? Looks related to nagios/smp/memory management. Seems to be recurring every 24hrs or so. This is ...
Blair's user avatar
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1 answer
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If SMP is disabled, does that mean I cannot use multicores? Or multiprocessors?

I've purchased a VPS for the sake of dev work, and had wished to install NetBSD under the Xen DomU guest. Unfortunately it is stated that this will work, however will not support SMP. Does this mean ...
Ronald H.'s user avatar
2 votes
1 answer
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Is one Xeon core enough to run a general website on my VPS?

I've purchased a VPS for dev work (at Linode) some time ago and am wishing to install NetBSD for the sake of experience, however its current support under the Xen hypervisor does not allow for SMP. I ...
Ronald H.'s user avatar
1 vote
2 answers
724 views

ESXi performance considerations with VM that requires many CPUs

I will be looking to buy a new server soon, and would like to consolidate servers into one VM server. I will have equivalent infrastructure offset, so this isn't a case of having all my eggs in one ...
John X Citizen's user avatar
7 votes
2 answers
4k views

Multiple vCPUs or multiple identical VMs, which is better?

I am looking to upgrade one of our servers, an 8 core server running VMware Server 2. The VMs it runs are mostly web, file, and email servers; specifically, it runs three webservers, 2 email/file ...
Josh's user avatar
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5 votes
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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 ...
Exodist's user avatar
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2 votes
3 answers
2k views

VMWare ESXi and IRQ balancing

VMWare ESXi 4.1 Guest: Linux kernel 2.6.32 64bit (tried older as well) In multi-CPU virtual machine all interrupts (eth0,ata_piix) are stuck to the single CPU. When running on the pure hardware, ...
disserman's user avatar
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Why windows process scheduler assign tasks to random CPUs?

I am on dual core C2D processor, Windows 7 (although this behavior is the same in all MS OSes I've seen). When I run any single threaded CPU-intensive task, it does not stick to 1 core, but rather ...
BarsMonster's user avatar
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1 answer
1k views

Does FreeBSD suffer from SMP issues?

This is not a FreeBSD vs [insert favorite linux server distro]. My interest is in knowing the why and how to remedy sch issues if they exist. Primarily, I'm looking to implement a FreeSwitch based ...
Mustafa Ismail Mustafa's user avatar
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3 answers
209 views

24 Core LAMP Issue

I have a 24 Core Opteron 8435 system with 48GB of RAM. However, the performance is way below that of our 6 Core Intel with 30GB of RAM. I wonder if anyone could this of why? We're running a Drupal ...
Khushil's user avatar
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24 Core Server Performance

I have a quad hexacore system based on the Opteron 8345 chips - that's 24 cores in all with 48GB of ram. This box was meant to replace the current six Intel core box which my current LAMP stack runs ...
Khushil's user avatar
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Emulate a SMP server with a Linux Cluster?

Is it possible to combine a few machines into a cluster and have it appears as a single server? For example, with such a cluster we can run a 32-thread CPU-bound process on 8 quad-core machines. Are ...
netvope's user avatar
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4 answers
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How to know when the kernel was last compiled?

I have installed a linux distro and I "think" it is vulnerable to kernel exploits. I have to update kernel but I need to know if it is really compiled in year 2003? How can I know if additional ...
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1 vote
1 answer
564 views

Should a core be "reserved" for the OS in a multi-core (SMP) Linux system?

If I plan to run eight applications on an eight core machine and expect all applications to utilise 100% cpu, will the OS "get enough time" for its own tasks or should I instead run seven applications ...
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6 votes
3 answers
15k views

How can I tell if irqbalance is doing anything?

I've looked into linux server tuning docs that mention installing irqbalance (http://www.irqbalance.org/) on SMP systems. I'm looking at it now on a quad-core system, and while "ps axf" can tell me ...
Stéphane's user avatar
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4 votes
3 answers
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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 ...
ManiacZX's user avatar
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2 votes
5 answers
381 views

Reclaiming an old server [closed]

I got a server, four-2.6Ghz AMD opteron and 10Gigs RAM on TYAN Thunder board, for free. The thing is massive and loud, I'd like to reclaim the processors and RAM into two smaller computers each with ...
nlucaroni's user avatar
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7 votes
5 answers
3k views

Why is CPU use so asymmetric on our 8-cpu SQL Server box?

I've noticed that the CPU usage on our 8-CPU database server, running SQL Server 2008, is not balanced at all. Here are the 1 day averages for a random day a while back, which is typical and ...
Jeff Atwood's user avatar
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2 votes
3 answers
127 views

Best hardware/software solution for parallel makes?

We've got a Linux-based build system in which a build consists of many different embedded targets (with correspondingly different drivers and featuresets enabled), each one built with another single ...
Allan Anderson's user avatar
2 votes
5 answers
4k views

How can I emulate more virtual CPU than physically available?

In VMWare you can use multiple CPU, but only as much as present on the host. Is there a way to use more CPU than physically available ? It would be to : test software designed to run on an ...
Steve Schnepp's user avatar