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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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 ...
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155 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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31 views

slow operation and low cpu usage in remote linux machine [closed]

I'm using a remote linux for simulation, I ssh into it for operation. Recently, my account in the remote machine is very slow, even type in a "ls", it takes seconds to show the result. I'm running ...
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2answers
42 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
9 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
64 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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1answer
59 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
34 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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19 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
23 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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32 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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3answers
54 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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40 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
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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2answers
142 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
24 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
89 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
48 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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1answer
66 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
42 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
49 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
55 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
65 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
127 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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47 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
53 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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13 views

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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34 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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37 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
95 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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124 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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2answers
341 views

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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215 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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1answer
69 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 ...
3
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2answers
180 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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70 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. ...
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2answers
113 views

/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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1answer
917 views

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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1answer
67 views

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 ...
2
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1answer
93 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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2answers
89 views

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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130 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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136 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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1answer
241 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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0answers
148 views

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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4answers
127 views

Run linux process at very very low priority?

I have regular process that not so important but will consume so much CPU power, and I have another process which is really important, but it spend most of the time idle, but when it got a job it ...
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0answers
94 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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1answer
60 views

Comparing Windows and Linux machine hardware

I have to compare Linux and Windows machine hardware? In windows system, I can open the My computer properties and see the details like processors, RAM Hard disks etc. Through task manager, I can see ...
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190 views

What's limiting my CPU usage in forked processes?

I am running some long-running programs (for scientific purposes) on a multi-core Linux box. The processes are controlled by a small daemon which restarts the next job when one finishes (I run 3-6 at ...
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1answer
82 views

why is my laptop-mode configuration being ignored?

I am running Debian GNU/Linux Jessie (testing) on my laptop. I enabled the systemd laptop-mode service: $ sudo laptop_mode Laptop mode enabled, active [unchanged] and in my ...