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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Linux & Linux-Software: Advantages of a multi core processor [closed]

I plan to get a new notebook and try to find out if a quad-core processor gives me any advantages over a regular dual-core machine. I use common Linux Distributions (Ubuntu, Arch etc.) and mostly ...
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335 views

How to ensure ssh via cgroups on centos?

When some cpu-intensive processes are running on the server, chances are that we could not log in to this machine with error 'operation timeout' via ssh command. According to this post answered by ...
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621 views

How to determine the maximum number to pass to make -j option?

I want to compile as fast as possible. Go figure. And would like to automate the choice of the number following the -j option. How can I programmatically choose that value, e.g. in a shell script? ...
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624 views

Telling Linux kernel *not* to use certain CPUs

I'm trying to run some benchmarks on a multicore machine and I'd like to tell the Linux kernel to simply avoid certain cores unless explicitly told to use them. The idea is that I could set aside a ...
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CPU Scheduling incredibly slow with large difference between total execution time and actual CPU time - Ubuntu Full-Disk Encryption enabled

Admittedly, I am running on a build that is no younger than five years old at this point and the system is not going to be incredibly fast. However, at the same time, the run-times I am observing are ...
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123 views

CPU Utilization & Memory Utilization script

I want to show CPU & Memory utilization. Like I use command of mpstat and get an output: 01:04:19 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s 01:04:19 PM all ...
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3answers
3k views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...
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33 views

How do I gather average cpu use in the background?

I'm trying to determine if an issue I'm having is related to cpu use, but my impacted application doesn't allow me to change terminals once it's open. It there a way I could dump only the cpu useage ...
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1answer
109 views

Enable virtualization with gigabyte ud3 990fx

I'm trying to get the virtualization running : I have the following settings: Mainboard: gigabyte ud3 990fx CPU: fx-9590 Kernel: 3.11.0-12-generic Linux Mint 17 In the bios both svm as well as ...
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205 views

Kill the process and restart server when memory is exceeded - bash and cron

I have a site on webfaction, using django and python. However, I have problem with memory. The problem arises, because I use external library, that can run forever (consuming much time and memory). ...
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1answer
115 views

Get list of supported opcodes

Is there a way to get a list of supported opcodes for a given architecture? Such as a listing in /proc similar to /proc/cpuinfo.
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1answer
233 views

Can one core on a multicore linux system be dedicated to one user-space app?

Can a core be dedicated to one user-space app (e.g. for the purpose of bit-banging GPIO without any interruptions)?
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1answer
202 views

Why is 'steal' time gradually increasing?

I'm tracking CPU usage on a VM on a lightly-loaded host. Everything appears to be functioning normally on all the VMs, but collectd is reporting a gradually increasing 'steal' time: The actual ...
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92 views

How to reduce temperature of my Toshiba with Slackware?

I have a Notebook Toshiba with Slackware 14.1 64bits $ lspci: 00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09) 00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 ...
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149 views

Isolating some CPU cores reduce average CPU usage of game servers

Hardware: FX8320 (8 cores) @ 4.4GHz, 16GB I run 10 TF2 game servers. Few days ago I isolated some CPU cores with line in linux grub config: isolcpus=5-7 The strange thing - individual CPU cores ...
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1answer
721 views

How to check whether my AIX is PPC OR PPC64?

My AIX machine is currently running on 6.1 OS. I would like to know whether it is on PPC OR PPC64, Is there any command other than arch which gives the information about PPC ?
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696 views

Are “kernel mode” and “user mode” hardware features or software features?

I read that there are two modes called “kernel mode” and “user mode” to handle execution of processes. (Understanding the Linux Kernel, 3rd Edition.) Is that a hardware switch (kernel/user) that is ...
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CPU always at 80°C while the system is idle

My system is quite unused at the moment: %Cpu(s): 10.3 us, 3.1 sy, 0.0 ni, 85.9 id, 0.7 wa, 0.0 hi, 0.0 si, 0.0 s but still the temps sensors give me are quite high: acpitz-virtual-0 Adapter:...
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1answer
583 views

CPU speed and cat /proc/cpuinfo

I use centos 6.4 64. I have old proc - CPU AMD Phenom II X4 810 (HDX810W) 2.6 GHz. However, when I execute the command cat /proc/cpuinfo I get the following: processor : 0 vendor_id : ...
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2answers
220 views

Pipe Viewer - Progress monitor performance consequence

I am writing a batch script to sort through gigs and gigs of data. All of the data is text but the script will take a long long time to execute. I would like to give some visual indication that the ...
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1answer
148 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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2answers
421 views

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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73 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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1answer
107 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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1answer
303 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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1answer
135 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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118 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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135 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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356 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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1answer
44 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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2answers
2k views

Kondemand process consumes most of my CPU

Following is the output from top: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3551 mysql 20 0 10.0g 84m 4052 S 9.4 0.1 544:39.87 mysqld 2311 root 20 0 0 ...
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1answer
93 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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1answer
2k 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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1answer
96 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 sysconf(...
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1answer
841 views

AIX CPU usage - how to know how many CPUs running?

Over AIX 6.1 - I do see the following output, it says I have 16 Max Physical CPUs; but there are only 8 active - why is that? The system will use the remaining 8 if needed? Or are they disabled? # ...
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2answers
226 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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1answer
73 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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1answer
190 views

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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1answer
368 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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1answer
491 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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0answers
112 views

/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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2answers
176 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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92 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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59 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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1answer
472 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, 66.3%sy,...
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2answers
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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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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 /proc/<PID>/...
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1answer
121 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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2answers
3k 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 > compress....
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167 views

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. ...