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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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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Difference between 'sar' and 'iostat' commands

With sar and iowait, we can get CPU time utilization. But, when I executed both commands, I could see significant differences in their outputs. > iostat && sar 1 1 Linux ...
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Figuring out physical cache layout in FreeBSD

I'm trying to figure out they physical cache layout of my CPU in FreeBSD 10. I see the following from sysctl kern.sched.topology_spec kern.sched.topology_spec: <groups> <group level="1" ...
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249 views

Exynos 5 DVFS or turning off cores in Ubuntu - Scaling frequency for one of the cores only (dual core) (cpufreq)

I was wondering if there is possible to scale only one of the cpu cores in the A15 in Exynos 5 ? I have tried using e.g cpufreq-set -c 1 -f 500MHz, but both cores are set to the same frequency. When ...
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476 views

cpufreqd does not control temperature plus shows no output

Since my laptop (an Acer Aspire 5750G running a Gentoo Linux with a not-quite-up-to-date kernel 2.6.39-r3 (a weird wLan hardware makes the update difficult)) tends to run rather hot I am trying to ...
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507 views

Is there a way to make your process use less CPU?

I want my device to use less CPU to save battery. I have a program that uses a large amount of it. nice won't help as all it does is change scheduling when CPU is at %100, while I don't want it to get ...
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2k views

Is my laptop's overheating issue CPU (Dual Core i5) or GPU (Nvidia 320M) related, and can I fix it in Linux Mint?

I've had the same problem in both Ubuntu 12.10 and Linux Mint 15. I've tried taking my Acer laptop apart (no mean feat for a noob like me) and cleaned and resat the GPU and CPU heatsinks and fan ...
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532 views

Was my CPU kinda broken?

Today I've received some message from mcelog utility, Processor 3 heated above trip temperature. Throttling enabled. Please check your system cooling. Performance will be impacted It happens when I ...
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Video player that uses multiple CPU/GPU cores in Linux?

I've got a relative with a four-cour AMD Phenom II 3.0 gHz CPU (can't remember exact specs) and ATI 5750 1GB graphics card, running Ubuntu 10.04. Right now I am aware of VLC and Mplayer for playing ...
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362 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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547 views

System IDLE Time > System Uptime?

I was testing out the linux api while working on something but got stuck on the following output. [Abhii@localhost net]$ cat /proc/uptime 39135.53 149657.73 As per specs the first number should be ...
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Find the PID of top CPU/MEM usage, save to a shell variable

Is there any way to get the PID of the top CPU/MEM usage, I need to use that in a script, top command doesn't seem to work for it.
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2answers
486 views

How to get CPU Percentage as a Counter?

I would like to monitor total CPU utilization percentage as a counter. The reason I would like it as a counter is that data won't be lost between samples (and I can have the graphing side calculate ...
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1answer
4k views

Ubuntu- How do I change clock speed from terminal? [duplicate]

The title of this question pretty much says it all. What command or program do I need to run in order to change the clock speed to a specific value I want? For example, I'm looking for something like ...
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1answer
3k 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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2answers
587 views

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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2answers
942 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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1answer
442 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 ...
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1answer
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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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2answers
92 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
58 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
932 views

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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Is there a way to dump a CPU's CPUID information?

I'm familiar with lshw, /proc/cpuinfo, etc. But is there a method for getting at a CPU's CPUID opcode?
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2answers
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Putting Linux processes on certain CPU cores [duplicate]

Possible Duplicate: How can I set the processor affinity of a process on Linux? Computer CPUs have many cores insde them nowadays. I have always wondered if there is a way to, when I start ...
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2answers
307 views

How to compare usage of memory by Window Managers?

I'd like to test a few window managers to see which of them takes less memory and CPU in certain time period (so is better choice for older computers). I'd like to make the tests myself (not to read a ...
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509 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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1answer
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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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1answer
109 views

Minimizing hardware interrupts

I am using a modified Linux kernel as a soft real-time OS, on a system that has an architecture like this: CPU1 and CPU2 have 8 cores each. I have 4 processes that need to be run with minimum ...
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1answer
416 views

Number of cores on FreeBSD

What would the equivalent of Debian's nproc be in FreeBSD? I'm trying to include this in a bash script variable so if it could just print out the number of cores that would be fantastic.
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1answer
214 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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1answer
1k views

Measuring CPU %steal on VMware and Hyper-V hypervisors

For Xen Linux guests, %steal time is readily available via top and other utilities. Is it possible to get this and related metrics from within a Linux guest when running a non-Xen hypervisor such as ...
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1answer
151 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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157 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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High Idle CPU / Low CPU Load average

After removing APC (alternative php cache), I noticed that there are less pagination access and less dirty pages but in the same time: High idle CPU Very low CPU load (relatively to the time before ...
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1answer
372 views

Determine the intel CPU family for C compiler?

I am checking the CPU information on a Linux server, and tuning options of the Intel C compiler icc for my C code running on the server's specific architecture. I am thinking about choosing the value ...
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337 views

Monitor single process to logfile perodicly

Based on this question, I would like to log the performance of a specific process, with a frequency of say one second, to a csv (comma separated value) log file. Something like: ...
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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 ...
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1answer
31 views

Set CPU affinity for the specific program?

How can I set CPU affinity for the specific program (say gzip) to always run on specific core or cores (core 1, for example)? I read about taskset, but can it be used before program is actually used ...
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1answer
48 views

Linux cgroups: limit CPU usage in absolute values which do not depend on CPU speed

I have a server with a 2.4GHz processor. And there are several cgroups, each one allowed to use 25% of CPU. That's equal to 600MHz. Then I replace the CPU with a faster one, let's say 3.0GHz. If I ...
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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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138 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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0answers
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Intel Xeon stuck at 800mhz CPU Freq on RHEL 6.5 [duplicate]

Currently running into a headache trying to figure out why my CPU speed is stuck as such a low frequency. After doing some research, I found that cpuspeedutil does actually control the state of the ...
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0answers
221 views

VPS freezes every few days (rcu_sched_state detected stall on CPU x)

Background: I have an Ubuntu 12.04 (64bit) in Xen virtualization environment. 1 GB RAM, 1 processor. Every few days I get the following error message: rcu_sched_state detected stall on cpu 0 ...
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Limit CPU cycles inside of Xen

I'd like to run some minimum-expectation benchmarks on EC2, but I'm having an issue of high variability in my output data. Specifically, they keep giving me more CPU than I'm minimally entitled to, ...
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1answer
1k views

/proc/cpuinfo showing zero cpu clock speed

I saw an interesting issue where the cpuinfo file from /proc filesystem shows the cpu clock speed as zero. It is a physical host with no virtualization. Can someone explain to me some probable reasons ...
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0answers
229 views

Unable to reduce core frequency freebsd

I'm working on a FreeBSD project where I need to maintain the temperature of the processor below a threshold value. In order to reduce the temperature I'm trying to dynamically change the frequency of ...
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276 views

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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Why I can not use all the 100% potential of CPU?

I am using my computer clusters to run a MD C program but I can not use full potential of those clusters. But the this node have 16 CPUs and I also only give 15 jobs for those CPUs. But I can not ...
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Should I care for applications that increase the system Load in order to prevent overheating?

I found that my "PCI Adapter" overheats when load is above 4.0 (having 4 cores). It does NOT overheat when the load is below 4.0 (but I had an overclocked memory that was causing trouble as I explain ...
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5answers
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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 ...