The CPU (Central Processing Unit), is the chip in the computer that actually performs the operations and calculations that are done as a program runs. It is essentially what executes a program.

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diabling cpu cores on quad core processor on linux

I want to disable 3 CPU cores and run my processor on a single core. I have used command:maxcpus=1. But after this I executed this command ls /sys/devices/system/cpu. It still shows ...
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How to check the cpu temperatures core by core?

I have a Phenom X3-8450e which has a total of 3 cores. But when I ran "sensors" on a terminal I got this: $ sensors atk0110-acpi-0 Adapter: ACPI interface Vcore Voltage: +0.99 V (min = ...
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top -bn1 not giving correct CPU usage

I am logging on to a node which I know has near 100% cpu usage (20 single process jobs using nearly 100% cpu each). When I use top interactively, the first iteration, it gives me about 20% ni and the ...
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134 views

Unexpected processor/core counts for AMD processor

I wanted to determine if a machine has hyperthreading enabled or not. To determine this, I used advice I found online, which operates as follows: physical_proc_count = `grep "physical id" ...
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40 views

Distributing CPU cores between cgroups and outside world

Is it possible to manage access to CPU cores in a similar fashion that memory limiting works? In particular I need to be able to dynamically create and destroy cgroups that will limit a particular ...
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Does QEMU/KVM use Intel AES instructions for encrypted qcow2 images if the host CPU has them?

The qcow2 image file format for KVM can use AES encryption. The encryption is applied at the cluster level: Each sector within each cluster is independently encrypted using AES Cipher Block ...
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66 views

What does the term 'Unix Processor' mean?

I have Googled around and found a few references to this term, but nothing which defines what it actually means. Does anyone here have experience with such a device? What features must a processor ...
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How can I know which IRQ is responsible of high CPU usage

I've moved a server from one mainboard to another due a disk controller failure. Since then I've noticed that constantly a 25% of one of the cores goes always to IRQ however I haven't managed myself ...
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50 views

How to get all CPU cache information without SU access

I am trying to find out the cache mapping scheme for all the levels of class of a linux server, however I do not have root access. I would just use DMIdecode for this but you need root access. Is ...
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40 views

cpulimit on a bash script which runs other commands

I have a bash script which runs other cpu-intensive commands . When I apply cpulimit on the bash script, the output of top shows processes for the commands inside the script still run without ...
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60 views

NAS: 100% system (kernel) cpu usage

I have a single core NAS My Live Duo. It runs Debian lenny release. I found via htop utility that it constantly use 100% of red cpu without any noticeable process to eat it. Than I checked via iostat ...
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52 views

Plot values returned by command output

I have a little script that prints the CPU temperature after each T period of time, so the output is something like this: 19/02/15,01:00 30 19/02/15,02:00 33 19/02/15,03:00 38 19/02/15,04:00 32 ...
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74 views

Which commands or operations can be used to put the cpu under intense load?

I would like to measure latencies during high cpu usage but I don't have benchmarking tools like stress and I can't install them. Which operations do you recommend to put the cpu under intense load? ...
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137 views

Is it safe to disable Frequency Scaling and CPU idle Power Management support for Real Time purposes?

I'm using a Raspberry Pi board and I would like to build a real time system. During the kernel configuration, I found the CONFIG_CPU_FREQ option, which (from the help section) allows you to change ...
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Invoking CPU Stress

Looking for an app or tool to invoke CPU usage on my virtual Linux and Unix guests. I found the app "stress" from a post on Stackoverflow, but curious what the Unix/Linux crowd would recommend.
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38 views

Identify machine configuration via code

I am writing a program where I need to know about the machine configuration. Code will run on Linux. I want to find the following: Number of CPU Cores Number of CPU Sockets Number of Disks If it's ...
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37 views

Solaris prstat - definition of “recent” time used in percentages

The man page for prstat (on Solaris 10 in my case) notes that that CPU % output is the "percentage of recent CPU time". I am trying to understand in more depth what "recent" means in this context - is ...
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383 views

Should I install the AMD/Intel microcode packages when running Debian?

Should I install the AMD/Intel microcode packages when running Debian? What exactly do they do, and when should/shouldn't I install them? Why are they in non-free?
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How do I know which processors are physical cores?

I've got an Intel i7 2700k here, and I'd like to know how I can tell which processors are physical and which are virtual (ie: hyperthreading). I'm currently running a Conky script to display my CPU ...
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61 views

Is there a way to change the number of processors a program sees?

Is there any way I can trick a program into thinking the system has fewer processors? To explain: I am debugging a program that creates as many threads as it has processors, using ...
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2answers
60 views

How can I find figure out why a machine has consistently 70%+ CPU usage?

My machine (Macbookpro, Archlinux) has consistently a CPU at 70%+, yet I have no clue why. This doesn't happen on MacOS, only on Linux. Using htop, I can see no program using more than 2% of CPU. ...
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55 views

linux + top command

I run the top command on my linux machine and I see that vim command take like 99.5% CPU PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND ...
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136 views

How can I find the CPU resource utilization of a process and all its children [duplicate]

If I have a process that spawns child processes, is there a good way to get a single number representing the combined CPU use of that process and its children? i.e is there a simple shell command ...
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How much RAM and CPU for a NTP server? [closed]

As a side project, I am thinking about adding a NTP server to pool.ntp.org. I would like to use CentOS basic, but how much RAM and CPU should I assign to a machine that will only be running ntpd (plus ...
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192 views

Why does a linux guest consume 100% of the host CPU under VirtualBox when the guest appears idle?

I am using VirtualBox on a Macbook Pro running Yosemite. My linux guests sometimes consume 100% of the host CPU (viewed in Activity Monitor) even though the guest is idle. Why is the host CPU ...
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/proc/stat - is guest counted into user time?

I have a quick question. In man page for /proc/stat this is not clear to me: Is guest and guest_nice time included in user time in /proc/stat? http://man7.org/linux/man-pages/man5/proc.5.html in ...
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86 views

Test if valid executable

Is there a (relatively) simple way to test if an executable not only exists, but is valid? By valid, I mean that an x86_64 Mach-O (OS X) executable will not run on an ARM Raspberry Pi. However, ...
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cacti Cannot display pictures

I install the nagios+cacti in the centos6.4, but the CPU picture drawing, others such as memory, processes are normal. This is why?
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46 views

arch linux on alienware 14

I've tried to install arch in my New alienware 14 But i got a few errors there, squashfs is making trouble and something is stuck in the CPUs. Does someone have experiences with that?
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40 views

What does the “k” metric mean in the “sa” output?

From man sa: k cpu-time averaged core usage, in 1k units My questions: How is it calculated? What is the significance?
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196 views

High %sy in top output, how to debug?

We have 2 identically configured servers and one of them is showing a high %sy while the other does not. This would seem to indicate that the system is busy doing something. Cpu(s): 28.1%us, ...
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200 views

Get CPU time for Benchmark in Bash Script

I'm using this Method here: http://giantdorks.org/alain/how-to-benchmark-individual-shell-script-sections-to-identify-slow-parts/ to Benchmark my Bashscript: RuntimePrint() { duration=$(echo ...
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How to enable safeguards for CPU temperature

My desktop has a nasty habit. When I have several high intensity applications running and my CPU is at maximum usage for a period of time, the core temperature rises and my computer auto-shuts off. ...
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204 views

Why PowerVM LPAR CPU utilization is negative

For a specific case I compute an PowerVM LPAR CPU utilization to be a large number less than zero. I am fetching the lpar sample event using: lslparutil -r lpar -m P750 --filter "lpar_names=i5lp5" ...
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339 views

System CPU Time and User CPU Time Calculation for a Process in Linux

I want to calculate CPU time consumption of a particular process in system mode and user mode using statistics present in /proc/<PID>. There are two fields utime and stime in ...
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87 views

Does it take time for process to utilize CPU?

I have a single-core x86 machine where I execute the burnP6(from cpuburn package) for 1 second and then kill the program: while true; do /usr/bin/burnP6 & sleep 1; pkill burnP6; sleep 1; done ...
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Where is PCB on linux

A PCB is a process control block , this is its definition on Wikipedia Process Control Block (PCB, also called Task Controlling Block,[1] Task Struct, or Switchframe) is a data structure in ...
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466 views

Less resource hungry alternative for piping `cat` into gzip for huge files

I have some files of which some are very large (like several GB), which I need to concatenate to one big file and then zip it, so something like this: cat file1 file2 file3 file4 | gzip > ...
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Changing CPU frequency programmatically

I have seen that standard CPU Frequency driver(comes with default package with linux kernel) can change the CPU frequency at runtime, when being used under the supervision of "Ondemand" governor. ...
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Total CPU usage and CPU usage under processes list is different in FreeBSD top implementation?

For some reason, overall CPU usage on my FreeBSD machine fluctuates between 1% and 85%, but the CPU usage in processes column never adds up to this amount. For example here the overall CPU usage is ...
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/proc/cpuinfo shows a single core under VirtualBox

My host machine is Windows 7, running an Intel Core i5 Processor. The Task Manager shows that I have 4 boxes under the Performance tab, which I assume to be 4 cores. However on my OEL guest (on ...
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Questions about CPU usage [closed]

How bad/normal/good is this CPU usage? Cpu0 : 14.4%us, 6.3%sy, 0.0%ni, 78.8%id, 0.0%wa, 0.0%hi, 0.5%si, 0.0%st Cpu1 : 88.3%us, 8.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 3.7%si, 0.0%st ...
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729 views

Setting running process affinity with taskset fails

I'm attempting to limit a process to a given number of CPU cores. According to the taskset man page and this documentation, the following should work: [fedora@dfarrell-opendaylight-cbench-devel ~]$ ...
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Find average CPU, vMem, sMem usage on 1, 5, and 15min

I am trying to find at time T the average CPU usage on 1, 5, and 15min, just like what you get from /proc/loadavg Same thing for virtual memory, and swap memory. I would be fine with a python ...
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175 views

Are there any alternatives to pidof? (smaller footprint)

Well, I've just found out that with extensive usage of pidof in very short intervals, the seemingly tiny tool can be a great CPU hog. (Source: top) On my older machine, it can easily reach 30 percent ...
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219 views

How to stop CPU fan in Linux?

I use an old computer. CPU fan creates big noise. Sometimes CPU fan suddenly stops and does not work for a long time, and CPU does not get heated in these long periods, because I use very light-weight ...
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Strange cpu usage values reported by pidstat

I have a script that reports the cpu usage of a specific program reading values from pidstat. The script launches as: pidstat -C ^frontend$ -h -l -p ALL 1 1 The values reported this way sometimes ...
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401 views

Elementary OS Gala using more than 100% CPU constantly

I am using ElementaryOS with the default Drivers and my Gala process is constantly using tons of CPU (sometimes more than 200%). I have looked everywhere but couldnt find a solution. I tried to ...
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127 views

Help troubleshoot a very slow system performance (Kubuntu, intel graphics) [closed]

As the title says the performance of my laptop is simply terrible. i3 M380 @ 2.53GHz, 4GB RAM (of which more than 2GB is rarely used), intel HD graphics (to external monitor through HDMI). It takes ...
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2answers
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Hyperthreading not detected by Linux [closed]

I have a Dell server with two Intel Xeon E5645 cpus, each cpu has 6 cores, and each core is hyperthreaded (i.e. should be equivalent to two virtual cores). I installed CentOS 6.2 on this server and it ...