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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Hyperthread and processors Clock, Size, and Capacity

When I enable hyperthreading, CPU size and capacity decrease to about half the non-hyperthreaded value. Since most of my processes use only two cores, should I disable hyperthreading? lshw -C ...
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lshw and lscpu disagree on caches - which is right?

I am trying to find out specifics about caches (in particular which caches are shared between cores and which are not) and have stumpled onto a inconsistency. sudo lshw says *-cache:0 ...
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4answers
707 views

script for logging all the stats for a particular process

I want to monitor CPU usage, disk read/write usage for a particular process, say ./myprocess. To monitor CPU top command seems to be a nice option and for read and write iotop seems to be a handy ...
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890 views

How to find which machines are idle on a cluster of many nodes

I run measurements on a cluster consisting of 32 nodes/machines. I do not require all nodes, only 4, for example. The problem is most of the time, the nodes are busy with other people running their ...
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382 views

CPU governor settings

What are CPU governor settings? How can I get their values, if they're set? I have 24 vCPUs on my machine.
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897 views

How does load average work with modern CPU's?

My understanding of load average lead me to be quite shocked with my current system. The CPU in my workstation is an i7 with hyperthreading enabled, and cat /proc/cpuinfo produces 4 'cpu's. That all ...
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2k views

Is the sum of all PIDs “utime” the total system utime?

In order to measure a user's total CPU time, I'm using the "utime" field out of /proc/[pid]/stat: utime %lu Amount of time that this process has been scheduled in user mode, measured in ...
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1answer
2k views

i686 versus i486 kernel on an Intel Core i3

I had installed Debian 6 Squeeze on my laptop a couple of weeks ago. Coming from Ubuntu, I did this by downloading the hybrid i386 image and booting it off a USB drive. Now on GRUB, I'm presented ...
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eldoc makes emacs use 100% cpu

When I use eldoc, I add this to .emacs: (add-hook 'emacs-lisp-mode-hook 'turn-on-eldoc-mode) (add-hook 'lisp-interaction-mode-hook 'turn-on-eldoc-mode) (add-hook 'ielm-mode-hook ...
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1answer
368 views

Process priority and cpu speed

In some devices the cpu speed is dynamic, being faster when there is more load. I was wondering if it is possible to set nice level or priority of a process so that it does not influence an increase ...
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869 views

Java problem - nearly looks like a virus?

I have a weird problem since about a week. When I wake up my computer from suspend, a java process starts and consumes about 170 % CPU capacity. I analyzed the java process a bit: it connects to ...
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492 views

How to find out how many cores (including emulated via HT and such) are avaliable to user?

I wonder how to get how many cores (including emulated via HT and such) are avaliable to user via bash shell-script command?
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How can I keep track of what's using the most CPU?

I use nagios to monitor my server. Once in a while I'll get a report that the CPU load is warning / critical, etc. Usually this happens at some odd hour or when I don't have the tools to immediately ...
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1answer
2k views

Why does top report the incorrect CPU usage?

I have a machine with Intel(R) Xeon(R) CPU E5520 visible as 16 logical cores (8 with HT). If I run something to eat CPU time (single threaded) top correctly reports 100% CPU usage for the process but ...
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2answers
330 views

How to identify if there is some power saving setting that powered down a processor in Linux

I have a linux server that apparently has two Intel Xeon X5670. /proc/cpuinfo shows 12 CPUs but dmidecode shows only one CPU and the other one is in the Unpopulated status like it is showing that ...
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2answers
2k views

/proc/cpuinfo “cache” category: L1, L2 or total?

When I look in /proc/cpuinfo, one of the lines tells me I have 6144 KB of cache. Is this L1 cache, L2 cache, or the sum of both of them? In any case, how do I find out how much L1 and L2 cache my ...
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How can I receive top-like CPU statistics from the shell?

I'm trying to get an accurate read of my used CPU (in percent) from top. This is the command I'm running for testing: top -n1 | awk '/Cpu\(s\):/ {print $2}' This returns: 10.7%us, Which is the ...
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2answers
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What tool(s) should I use to test my hardware for errors?

Are there any Linux tools (command line, or Live CD) that will test hardware components for errors (hard drive, RAM, CPU, graphics card, buses) and show me some detailed output with wrong parts etc.?
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304 views

Loading speedstep_centrino kernel module

Because of a noisy fan in my laptop, I need to change CPU frequency and for this task I need to load the appropriate kernel module. The CPU in my laptop Acer TravelMate 4002WLMi is: $ cat ...
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1answer
2k views

Setting CPU frequency guidelines

I'm changing my CPU frequency because of noisy fan. I used sudo cpufreq-selector -g powersave for this purpose, but I replaced my Linux system Xubuntu with Lubuntu because it utilizes better ...
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1answer
577 views

Only one CPU core is active on Fedora 16

I've upgraded from F15 to F16 and noticed that I have a problems with hardware detection. Upon loading I can see message like ... CPU#1 not responding ... on the screen. It disappears and I can ...
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2answers
318 views

Is there a log of past threads that are now closed?

Sometimes, I have a rogue Java process which takes up 100% of my CPU and makes it jump about 30C in temperature (usually resulting in a crash if not killed). Problem is, I can never really identify ...
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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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3answers
611 views

How 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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369 views

Measuring CPU and Memory per user to distribute “cost” of a server

How should I implement approximately correct per-user monitoring on a server? I want a way to split the cost of a server between the users based on their usage. On newer machines (RHEL6) I would use ...
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Limit process to one cpu core

How to limit process to one cpu core ? Something similar to ulimit or cpulimit would be nice. (Just to ensure: I do NOT want to limit percentage usage or time of execution. I want to force app (with ...
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Why is kworker consuming so many resources on Linux 3.0.0-12-server?

Last Friday I upgraded my Ubuntu server to 11.10, which now runs with a 3.0.0-12-server kernel. Since then the overall performance has dropped dramatically. Before the upgrade the system load was ...
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2answers
541 views

How to maximize the use of computer performance Core i7 [closed]

How to maximize the use of computer performance Core i7 960 / 12GB Ram?. My operating system is Debian 6 (Linux kernel - 3.0.0-1-amd64). I think it does not work very quickly. Looking for some ways to ...
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3answers
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CPU locked at lowest frequency, cpufreqd says it won't manage it?

I have a Dell Latitude D600 running CrunchBang Statler (Debian Squeeze-based) with a 1.4GHz Pentium M. I noticed in Conky that my CPU freq is stuck at 600MHz, even when doing CPU-intensive things like ...
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2answers
3k views

Get CPU utilization stats from C program

I want to read the CPU utilization stats from a C program, I am interested in the percentage of use of CPU, steal time etc. These stats are shown in the 3rd row from the top command. I tried to parse ...
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3answers
8k views

How to find which Process is causing High CPU usage

Is there any way to find out from terminal which process is causing high CPU Usage ? It would also be useful to order processes in descending order of cpu Usage
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Is there a way to limit overall CPU consumption?

My laptop (an HP with an i3 chip) overheats like crazy every time I run a resource heavy process (like a large compilation, extracting large tarballs or ... playing Flash). I am currently looking ...
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In Linux “top” command what are us, sy, ni, id, wa, hi, si and st (for CPU usage)?

When I issue $ top in linux, I get a result similar to this (see here). One of the lines has CPU usage information represented like this: Cpu(s): 87.3%us, 1.2%sy, 0.0%ni, 27.6%id, 0.0%wa, ...
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How to get information about word, address size, address bus size, data bus size and instruction bus size?

I was wondering how to get information about the following things from the command line in Linux: word (i.e. the size that the CPU can process at one time, which may not be the OS bit-depth), ...
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1answer
5k views

What are software and hardware interrupts, and how are they processed?

I am not sure if I understand the concept of hardware and software interrupts. If I understand correctly, the purpose of a hardware interrupt is to get some attention of the CPU, part of implementing ...
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Xorg increases cpu usage over time

I've had quite a strange phenomenon with Xorg for some time now: After logging in to my laptop (specifics below) the cpu consumption of Xorg increases monotonically, even if the computer is idle and ...
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2answers
921 views

Program to test CPU load and process priority

I am running some test on Amazon EC2 instances and we want to make the CPU always busy at above 80%. What I have is a program main that needs to run in high priority and I want to launch another ...
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2answers
481 views

Finding MFLOPS using Linux

How can I find out the Mflops on my linux computer? I can see the bogomips on my /proc/cpuinfo but I don't see any Mflops on that file: $ cat /proc/cpuinfo | grep -ie mips -ie flops bogomips : ...
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916 views

How to find if hyperthreading is enabled on FreeBSD

Is it possible to find out if hyperthreading is enabled within the BSD kernel of a given machine without watching the boot up sequence?
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1answer
1k views

Why Process CPU % Usage larger than Total CPU Time

When I run the TOP command, a process shows 1208% cpu usage and the total CPU usr time is 81.7% with IRIX mode on. When I change to IRIX mode off, the process shows 99% cpu usage and the total user ...
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416 views

Overheating results in system shutdown

I have been having an overheating issue which makes my laptop shutdown immediately. Is there anyway to monitor the temperature from the sensor and scale down the CPU frequency to avoid that problem? ...
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3answers
1k views

How to limit resource usage to save CPU+RAM for a certain process?

I have a dev server on which sshd sometimes stops working because the machine runs out of RAM. Yes we are running low on memory and upgrading is not a feasible choice right now. What I want to do is ...
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6k views

How to check that AES-NI is supported by my CPU?

Howcan I check if my CPU supports the AES-NI instruction set under Linux/UNIX.
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1answer
740 views

Overclocking software for Linux?

Is most overclocking done strictly at the BIOS level, or is there a way to do it from a running operating system? And if so, is there a way to do it from Linux? I'm running Ubuntu presently and am ...
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2answers
2k views

Slow down the CPU

I tried to slow down my CPU with powernowd and cpufreq-selector. I hoped that with lower frequency it will be less hot and I won't hear my fan every time I will run internet radio. I used the ...
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333 views

Queries about top command

top command shows the process cpu utilization, and it when we sum the cpu utilization of all the processes then it goes greater than 100%. And how can it shows the cpu utilization of each process( ...
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performance monitoring

Is there some performace monitoring tool which would run in background gathering info about all system activity? Somethimes my system (Arch linux, 32 bit) slows down terribly and the top utility ...
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3k views

Understanding top and load average

I'm observing a high load average on a certain machine (about 9) in all three load fields. I understand load as the number of processes in state "run" / currently desiring CPU time. Am I correct at ...
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6k views

Run process with higher priority

I want to run mplayer with higher priority than any other processes, including the IO-processes. How can I do that?
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397 views

xorg performance in openoffice

I've just been monitoring my cpu usage in openoffice calc when cells have been copied vs when they haven't and seen a dramatic increase in cpu usage for the Xorg process. The additional rendering ...