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.

learn more… | top users | synonyms (1)

4
votes
2answers
724 views

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 ...
4
votes
3answers
2k views

On Ubuntu Linux, is it normal for mandb to run continuously (apparently in the background)?

I have access to a Ubuntu Linux node at my institution. The nodes are shared among the group, but typically I am the only person who uses this particular node. I am running a calculation in parallel ...
4
votes
2answers
658 views

How can we use the command 'top‘ to monitor the total CPU usage and each processor usage simultaneously?

You know that we can use the command top to monitor the real-time CPU usage and toggle the result display to the per-processor view by pressing key 1. The disadvantage of it is you can only monitor ...
4
votes
1answer
177 views

Execution time and resources after processes that has been running for so long

This might be a basic question, but I am getting hard time finding an answer to it. I am using RHEL6. After running any process that takes significant cpu time, I get a line that tells (I guess) the ...
4
votes
1answer
3k 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 ...
4
votes
2answers
3k 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 ...
4
votes
1answer
69 views

Get CPU usage for single process

I've got a problem getting a real-time CPU usage of a single process (by its PID). I'd like to setup a watchdog for the CPU usage of a process because it's suddenly reaching 100% of the CPU usage ...
4
votes
1answer
322 views

Control cpu freq depending on ac/battery state

How can I make my linux system (ubuntu) automatically choose the performance governor when it works with ac and switch automatically to ondemand when it is on battery (and vice versa)? Is it also ...
4
votes
2answers
2k views

CPU usage of KVM

I have a linux host with 4 KVM linux guests. All the guest are pretty much idle, having a load of <0.1 inside the guest. Now, if I do a top on the host, each KVM process is using something about ...
4
votes
4answers
876 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 ...
4
votes
1answer
64 views

Find out if CPU supports dynamic speed setting

I need to find out in my script if a (potentially legacy) CPU supports dynamic speed setting, and eventually get value of maximum and current speed. What makes it more complicated is that I need to ...
4
votes
1answer
3k 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 ...
3
votes
3answers
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 ...
3
votes
2answers
2k views

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), ...
3
votes
2answers
152 views

Understanding %CPU while running top command [duplicate]

I am trying to understand what does %CPU means when I run top. I am seeing %CPU for my application as 400 or 500 most of the times. Does anyone knows what does this mean? What number is a high ...
3
votes
1answer
49 views

Is there a tool that I can use to create a diagram of my system's architecture?

I'm looking for a tool that can create both graphical files as well as text based ASCII representations of my system's CPU & motherboard architectures.
3
votes
3answers
766 views

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.
3
votes
2answers
377 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 ...
3
votes
3answers
5k views

Bash script that automatically kills processes when CPU/memory usage gets too high

I have created a script that kills processes if CPU and/or memory usage hits 80%. It creates a list of killed processes when this happens. What can I do to improve it? while [ 1 ]; do echo echo ...
3
votes
1answer
223 views

How to set the CPU freq. in Linux?

I'm using this ARM9 SAM9G25 embedded system, that when switched on, is only online for a few seconds and because I want to speed up the whole process, I'd like to check the CPU frequency, and set it ...
3
votes
1answer
208 views

How accurate is Conky?

I'm on Crunchbang 64 bit, Conky shows that I'm using 4% of my CPU. But I can feel the CPU burning so hot, got Spotify, Chrome and couple other apps running. On windows 7 chrome uses about half of the ...
3
votes
1answer
159 views

How to measure the clock pulse of my computer manually?

My PC has two processors, and I know that each one runs at 1.86 GHz. I have just read about clock cycles and I only have a (very) rough understanding, so I apologize beforehand if my question is so ...
3
votes
2answers
2k views

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 ...
3
votes
3answers
441 views

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 ...
3
votes
2answers
1k 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 ...
3
votes
1answer
95 views

What's the correct value to base the maximum number of CPU's to sched_setaffinity to?

I have some confusion as to what's the correct value to use for the number of CPU's I can use to make a CPU_SET for a sched_setaffinity call on my system. My /proc/cpuinfo file: processor : 0 ...
3
votes
1answer
172 views

How to assign tasks to GPU

I have found a benchmark from computerbase.de (http://www.computerbase.de/artikel/grafikkarten/2013/intel-haswell-grafik-fuer-desktop-pcs-im-test/3/ in german) where in one case a task (here video ...
3
votes
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 ...
3
votes
2answers
435 views

Will enabling Hyper-Threading create two virtual half-speed processors?

If I enable Hyper-Threading for my netbook which has an Intel Atom (1.6 GHz) will the kernel see two virtual 800 MHz processors?
3
votes
2answers
70 views

What does it mean exactly when a processes “Time” has stopped in top?

I'll be looking into why we're getting critical swap alerts, and I'll find something like: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP COMMAND 14683 user1 30 10 16.0g 772m ...
3
votes
1answer
712 views

Do I have PCLMUL instruction set support?

Here are the flags from /proc/cpuinfo: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc ...
3
votes
1answer
744 views

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 ...
3
votes
2answers
55 views

CPU percentage of a single process

How do I get the average CPU percentage (for every second) consumed by a single process since it starts until it ends (exists)? Could I make this with Top?
3
votes
1answer
114 views

Slow down CPU when it heats up

I run Gentoo Linux on my laptop. I have an issue, though, where if I'm building some very large piece of software (as I do fairly frequently, since the purpose of this laptop is development), the CPU ...
3
votes
1answer
368 views

Mint fan control

I've installed Mint 15 on my Alienware m14x and can't figure out one thing. For some reason CPU overheats and fan does not respond to that. It always stays calm and quiet. How exactly I can change ...
3
votes
2answers
2k views

Hyperthreading not detected by Linux

Problem solved! After speaking to Dell's support they realized that I had to remove the option acpi=off from my /boot/grub/menu.1st config file. Apparently ACPI support is essential for ...
3
votes
1answer
615 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 ...
3
votes
2answers
1k 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?
3
votes
0answers
38 views

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" ...
3
votes
0answers
162 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 ...
3
votes
1answer
1k 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 ...
2
votes
4answers
197 views

Number of processors in /proc/cpuinfo

While i was learning about cpu load i came to know that it depends on numbers of core. if i have 2 cores then load 2 will give 100% cpu utilization. So i tried to find out cores.( i already know that ...
2
votes
2answers
211 views

Why load is high despite the fact that neither CPU or disk is overused

I'm getting the following output from top: Cpu(s): 43.8%us, 32.5%sy, 4.8%ni, 2.0%id, 15.6%wa, 0.2%hi, 1.2%si, 0.0%st Mem: 16331504k total, 15759412k used, 572092k free, 4575980k buffers ...
2
votes
3answers
2k views

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 ...
2
votes
1answer
376 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 ...
2
votes
2answers
1k views

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.
2
votes
4answers
7k views

How to get CPU info on a vmware guest

This is a server that is running on Vmware ESXi: SERVER:/root # cat /etc/SuSE\-release SUSE Linux Enterprise Server 11 (x86_64) VERSION = 11 PATCHLEVEL = 2 ...
2
votes
3answers
3k views

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 ...
2
votes
2answers
238 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 ...
2
votes
1answer
2k views

CPU and core usage stats

I'm running some programs on a server and I would like to know how much % cpu I'm taking up and how many cores are being utilised by my process. To clarify, the server has 16 CPUs, all quad-core. I ...