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Questions tagged [multi-core]

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HaProxy Configurations Error while setting up multi proc environment

I want to achieve 6000/sec Requests and trying to setup HaProxy with muli proc Settings but Getting this Error. cpu-map expects a process number including 'all', 'odd', 'even', or a number from 1 ...
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2answers
53 views

Scaling Apache/PHP is as simple as maximizing the number of CPU cores?

I have an Linux/Debian server with Intel i7 CPU with 4 cores and 8 threads. When I run my heavy duty Apache/PHP job it uses 1 thread, and when I run concurrent Apache/PHP jobs they each use their own ...
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2answers
459 views

Scan the full filesystem in parallel with clamscan

I run a clamav scan weekly on my servers. There is one server with a raid6 cluster of 30TB of disk space where the scan take more than 24h to run. So I wonder how can I run clamscan on the whole ...
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1answer
129 views

Is it possible to configure Apache-Tomcat with specific number of cores?

Is it possible to configure an Apache Tomcat (v7) with an specific number of cores? How can I specify it? I'm developing in a machine with 4 cores, but when uploading to the server with 8 cores, the ...
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1answer
31 views

Core ids are not consecutive

I encountered a weird situation on a 28-core Intel Skylake system (kernel: 4.4.0-121-generic #145-Ubuntu SMP, hyperthreading is disabled): cat /proc/cpuinfo |grep "core id" core id : 0 core id ...
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0answers
52 views

MPI job hangs on one specific node only

I'll preface this with the note that I'm not a sysadmin (anymore)- I'm a scientist, but I'm trying to help our sysadmins out here. So I can't immediately try things that require hardware changes or ...
2
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1answer
387 views

per processs core limit to allevate high sy/kernel cpu usage

My understanding is high kernel/sy CPU usage is a symptom of network and disk IO or issues of RAM throughput. #516139. However, I suspect in the case below, over allocating threads is giving the ...
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2answers
757 views

NUMA CPU numbering in Linux

I have access to two NUMA servers. One of them is Dell R720 and has these CPUs: $ cat /proc/cpuinfo |grep Xeon|sort|uniq -c 24 model name : Intel(R) Xeon(R) CPU E5-2630L v2 @ 2.40GHz The other ...
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1answer
70 views

RHEL: 4 Cores available but only 1 used

I'm running a heavy java process on my rhel. It had 8GB of RAM and 1 core for CPU. With the help top and htop I saw there was not enough CPU available for this process. I added 3 extra cores in ...
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2answers
783 views

How to get all processes running on each CPU core in Ubuntu?

I am working on Ubuntu14.04 server and it has 48 CPU cores. I am seeing there is high CPU usage on one core from sar information. So I want to know which processes are running on that core. How should ...
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0answers
179 views

Linux KVM host cpu core to client ratio

I know it's a common question but I need to ask anyway, just to clarify: How many cores should I assign to my kvm clients? The host machine has 1 CPU with 8 cores. How many cores should I give the ...
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0answers
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RHEL 7 allocate physical cores and rams for users

Dears, Back at work we have Dell blade server with 64 physical cores, and we intend to use heavy simulations on softwares by multiple users. My question: Is there a way to assign certain number of ...
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1answer
33 views

Multi-core processor - what is the meaning of this? [closed]

I am baffled by the terminologies like Core i3, Core i5 etc. Does Core i3 means three physical CPU's (three physical Chips)? or three cpu's in a SINGLE CHIP? I did try to find this information online,...
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2answers
1k views

Stand alone single thread optimized server vs vm running on VMWare

I apologize for the length of my post. We recently converted our business system to a product that is licensed by the number of Cores. We purchased the 2 core license and are currently running it on ...
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3answers
1k views

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 ...
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2answers
793 views

Does changing CPU cores on VMware cause any problems?

I remember once I tried to add CPU cores and virtual sockets to a VPS running windows server 2003 and it didn't work and somehow it became unstable and I couldn't use it anymore . Now I'm running ...
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1answer
65 views

Processing power and core allocation in VM

I would like to know how if it is possible to harvest the full power of a CPU by allocating a lesser number of cores compared to the physical number of cores in a virtual machine. What I mean is: ...
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1answer
180 views

PHP - Multicore for hashing

I have a server with 2 intel xeons on it, this gives me quite a lot of cores. And on that server i have an app, that uses php to hash passwords in blowfish. But the issue is php is not using all the ...
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7answers
2k views

How do one check huge files identity if hashing is CPU bound?

For small files hashing is just ok, but with huge ones you can easily find md5sum is CPU bound. Is there any hashing algorithm able to scale out on multiple cores? Any workarounds? Ideas? Anything? :)
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1answer
3k views

How does CPU affinity interact with cgroups in Linux?

I'm trying to run multi-threaded benchmarks on a set of isolated CPUs. To cut a long story short, I initially tried with isolcpus and taskset, but hit problems. Now I'm playing with cgroups/csets. I ...
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0answers
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Dell 2970 Server dual Opteron 2435's_Ubuntu OS incorrectly reporting CPU's

The 2970 has BIOS version 4.2.1. lshw -c processor gives me correct cpu information and core count = 12 cores. cat /proc/cpuinfo and lscpu both give me 8 cores (incorrect). OS = Ubuntu 14.04 LTS I had ...
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1answer
107 views

number of cores available on a server

I need to find out, how many cores are available on a server at that moment. For example, it is a 8 core machine and running at 50% CPU utilization. Can this be assumed as 4 cores are available? or is ...
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2answers
33 views

Why limit execution cores if you're not an cloud provider

We're maintaining development of a system installed at a customer site on their virtual server. This application will at times need to run heavy work. However it's only been granted a single core. I ...
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1answer
249 views

Apache doesnt appear to be using multiple cores

I have a dedicated server with 16gb RAM with a Xeon E5504(8cores @2.0GHZ) running with Centos 7. I ran the top command and can see that 7 of the cores are close to idle most of the time and then one ...
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2answers
124 views

For php webserver, what is faster, 1x 24-core server or 3x 8-core servers? [closed]

Pricing at Dell, it seems I can either get a single R430 or 3x R220's. The R220's would have 4C/8T processors, giving 24 threads. The R430 would have 2x 6C/12T processors giving again 24 threads. For ...
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1answer
57 views

Tasks on server stay in sleeping

I logged into a server with multiprocessors and started 20 python programs, each processing part of my data. However, it cost too much time so I checked top and found all ipython processes are in ...
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4answers
8k views

When should I consider a 2 socket motherboard for Server? [duplicate]

We are buying a new server and the idea of dual socket motherboard comes up. Is 2 socket motherboard worth the price and hassle for an application that hosts a couple of websites and databases for a ...
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2answers
10k views

Java: Limit the number of cores a JVM can use

Multiple users are running java applications on a 60-core compute server (Linux/Ubuntu-based). There are different applications and most of them are not developed in-house. While the sysadmin thinks ...
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2answers
522 views

how to check if a process with heavy io usage is running properly

I am now managing a computer cluster for scientific computing. Some processes in the cluster need heavy io usage. Now I find such a process: Its state changes rapidly between DOWN and RUN and its cpu ...
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2answers
140 views

CPU core utilization is automatic?

I have a 512MB KVM Debian OS VPS running several game servers and several sql enabled websites. Currently I have 1 vCPU core and it stays around 15% usage. If I were to get an extra vCPU core will ...
5
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1answer
3k views

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 ...
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0answers
421 views

Dual core CPUs stall with Docker on Ubuntu Linux

I have seen performance degradation after half an hour to one hour with machines running Celery (Django/Python), or Storm under Docker containers with Ubuntu base on Dual-core CPUs on AWS. I see ...
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1answer
5k views

difference between taskset and cpuset

I'm trying to reduce the latency of my linux network application. I've learned that there are two tools for "binding" a program to particular CPU core: taskset and cpuset. Which one should I prefer? ...
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2answers
13k views

Find process causing IO wait time

mpstat -P ALL shows high %wa time on a single core from an 8 core CPU and I'm trying to figure out what's writing to disk. So how can I figure out what is running on that CPU core?
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1answer
294 views

Taskset not working properly in OpenVZ container

In a Debian OpenVZ container, I'm trying to use taskset to pin a process to a core, but it doesn't work: root@foo:/# taskset -c -p 0 1754 pid 1754's current affinity list: 0-7 pid 1754's new affinity ...
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6answers
2k views

When is it time to add more cores to your virtual server? [closed]

I have a Linux (RHEL 5.8) server with Java 7 and Tomcat 7. The performance is poor, and I am pretty sure it's the DB queries that are slow. We have 2 cores right now, and load average never exceeds ...
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1answer
2k views

Does installing more CPUs (Intel) than indicated by “Max CPU Configuration” prevent all cores from being used?

I am looking at a server that has 4 physical processors, the Intel documentation indicates they are 6 core processors but this WMI query WMIC CPU Get NumberOfCores, NumberOfLogicalProcessors /Format:...
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4answers
634 views

Why is it so hard to get servers with Lot of Ram, but few cores?

SQL server has a very high per core license cost, but for a lot of workloads benefits more from lots of RAM. his is now even more of the case with in-memory tables. Even if a server with 4 cores ...
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4answers
472 views

Does using all cores reduce efficiency?

I have a program (well, php script) which does some pretty heavy text searching - it loads a 2mb and 40mb file and searches through them to find where each word that appears in the first is present in ...
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1answer
632 views

Windows Server 2012 - CPU utilization

I have Windows Server 2012 machine which has 32 cores. In Task Manager, it shows 32 cores and 64 logical processors, because of hyperthreading. My CPU utilization is in the screenshot below: Can ...
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1answer
429 views

How strongly does the number of processors influence on the performance? [closed]

I use Windows Server 2008 R2 with Hyper-V. I can increase the number of processors in Hyper-V settings (http://www.youtube.com/watch?v=NQCMT-O6bMM). How strongly it will increase the performance? ...
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1answer
742 views

Can I improve speed in Hyper-V?

I use Windows Server 2008 R2 (it is host) with Hyper-V and a guest running Ubuntu 12.04 LTC. It is my settings: RAM 32768 Cores (virtual processes) 4. (I need 12) I also use virtual hard drive with ...
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2answers
3k views

VMware - Can a 1 vCPU VM use more than 1 physical core at the same time?

Assume I have a physical ESX host with ONE quad-core processor and hyper-threading disabled. This means it has a total of 4 physical cores or pCPUs. I create a single VM on this VMware host. I assign ...
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1answer
858 views

KVM host only using one core out of 8

This KVM host is only running one VM/guest right now, and it is running with -smp 1. Top shows only the first core being active. Is that expected when using -smp1? The guest OS is Windows XP. The ...
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3answers
915 views

2 x Dual Core vs 1 x Quad Core Performance

A license restriction limits us to 2 x dual core servers, or one 1 x quad core server. Should we see better performance running 2 x Dual Core servers or 1 x Quad Core? Dual Core processors are harder ...
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1answer
3k views

MySQL MyISAM multi-core optimization

I've noticed that our app does not respond to requests when a demanding request is in execution. Running top seems to identify the source of the problem: top - 13:54:25 up 1 day, 13:43, 2 users, ...
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2answers
100 views

Multi-CPU server with CPUs of differing core counts

Is it possible to have a multi-CPU server where the CPUs do not necessarily have the same number of core counts? For example, a group of 4 at dual core and a group of four at quad core? This ...
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1answer
60 views

Tracking down high CPU core utilisation

I have a system with 24 cores and for some reason only the first core is at 100% utilisation while the others are in the range of 20-25%. I would like to get all processes that are running on the ...
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3answers
48k 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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2answers
18k views

Is there a limitations to the number of cores on Windows 7 64 operating system?

Is there a limitation to the number of cores a Windows 7 64 bit operating system can support? I am planning to use that as render server. Rendering software is truly multi-threaded. I am getting a 32 ...