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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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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12 views

Java programs hang, unless pinned to single core

I'm having issues with java applications being completely unresponsive unless I pin them to s single core. The strange thing is that I'm using the exact same configuration on two different machines ...
78
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4answers
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What do the flags in /proc/cpuinfo mean?

How can I tell whether my processor has a particular feature? (64-bit instruction set, hardware-assisted virtualization, cryptographic accelerators, etc.) I know that the file /proc/cpuinfo contains ...
2
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1answer
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/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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1answer
26 views

Threads vs interrupts

What does it mean when threads are time-sliced? Does that mean they work as interrupts, don't exit while routine is not finished? Or it executes one instruction from one thread then one instruction ...
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3answers
95 views

How to know number of cores of a system in Linux?

I wanted to find out how many cores my system has. So I searched the same question in google. i got some command like: $ lscpu command. When i tried this command, it gave me the following result: In ...
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0answers
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CPU Handling with Delayed Work [migrated]

Hey so I'm looking at this function in the kernel source code. I'm trying to figure out how Linux handles the situation where a task cannot be scheduled on the local CPU. /** * queue_delayed_work - ...
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2answers
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 ...
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0answers
6 views

/proc filesystem - getting useful information

I'm trying to understand the values in /proc/PID/status. I want to calculate cpu% & mem% used by PID, similar to top bash command. For Memory percentage usage I can do the following (correct me ...
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2answers
45 views

Is there a good resource monitoring tool in linux?

I've been looking for a good resource monitor in linux for a couple of hours and all I have found is conky. Specifically I've been looking for something to monitor my core clock speeds. I've found ...
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1answer
1k views

Intel Turbo Boost apparently activated for no reason?

The other day, I reinstalled my operating system (Crunchbang, fork of Debian). For some reason my fan has been running at full speed (and blowing colder-than-room-temperature air) even though I'm ...
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16 views

cpu temperature is higher than usual after installing xubuntu

I have installed Xubuntu 14.04 on Asus S550CB but the system becomes warmer than usual. So I tried to configure lm-sensors and saw cpu temperature is about 50 degrees. I guessed that some drivers are ...
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35 views

Resource (CPU time and memory) limitation and termination of a process upon violation in Linux

The problem: Given a process, limit the resources it and its child-processes can use. I.e. set CPU time and virtual memory quotas. When the process group exceeds one of the limits, terminate it, ...
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1answer
776 views

Linux Mint CPU cores balancing and high temprature

I'm using Linux Mint. My laptop has a Corei5 CPU. When I check the system monitor, it shows that the CPU 1 usage is between 90 to 100% and CPU 2,3,4 are less than 5%. why it doesn't balance processes ...
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1answer
29 views

Monitor Cpu & Ram Uasge Via Web

Sorry about that newbie question. But does anyone know how to make or where to find a script that will monitor CPU and ram usage, so i will be able to use it at my admin panel on web? I'm running a ...
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0answers
20 views

Get AMD 8320 CPU temp?

I'm looking to get the CPU temperature of my AMD FX-8320 chip. I have lm-sensors installed and I've run sensors-detect saying yes to all of the prompts. I also have the kmod system service running and ...
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0answers
34 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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4answers
13k 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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4answers
3k views

How come I installed Ubuntu 64 bit on a Pentium 4 machine?

I have just tried booting the Ubuntu 10.10 64 bit live USB on this machine and to my amazement everything works fine. I even installed the system, after which I checked with uname -a and the result is ...
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Getting cpu usage same every time.

When I execute following command to get cpu usage , I get nice + user cpu usage. top -b -n1 | grep "Cpu(s)" | awk '{print $2 + $4}' Output: 14.5 Here I am getting problem is that the output ...
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2answers
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Why is the range of load average not 0-1+ for all cpu's together?

I know that load average is 0-1(or 0-1024) per cpu. E.g a busy quad-core can have a load average of 4.0 or higher. (e.g if there are many tasks). I understand it can be huge like 100+ etc. I also ...
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5answers
2k 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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0answers
100 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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3answers
106 views

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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1answer
29 views

Show CPU core usage for parent process and its child processes

Is it possible to display CPU core usage just for a single process and its child processes on Linux?
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2answers
52 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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1answer
69 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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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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2answers
57 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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35 views

High %sy cpu usage , server is very slow

On one of the server we are noticing high %sy usage due to which server is very slow. Below is strace count for syscall. What will be the reason for high %sy usage. % time seconds usecs/call ...
0
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1answer
40 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
367 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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1answer
166 views

Whats the history behind the fork bomb?

I have read other questions about its work and other things that Fork bombs operate both by consuming CPU time in the process of forking, and by saturating the operating system's process table. A ...
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27 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
33 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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0answers
83 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
52 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
54 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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0answers
47 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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1answer
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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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50 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 ...
0
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1answer
83 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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126 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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4answers
4k 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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vote
1answer
227 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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53 views

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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2answers
521 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
339 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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4answers
238 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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2answers
82 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 ...