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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Disable CPU scaling with U 1404

I know there are a lot of things about this topic but I couldn't find anything not older than 4 years. As the stuff develops so fast I hope it is fine to ask again a few years later. What is ...
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4answers
116 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 ...
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NVIDIA: could not open the device file /dev/nvidia0 (Operation not permitted)

When I try to run chrome/ium on command line it says NVIDIA: could not open the device file /dev/nvidia0` (Operation not permitted) I don't know whether its related with high CPU usage on ...
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72 views

diabling cpu cores on quad core processor on linux

I want to disable 3 CPU cores and run my processor on a single core. I have used command:maxcpus=1. But after this I executed this command ls /sys/devices/system/cpu. It still shows ...
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107 views

How to check the cpu temperatures core by core?

I have a Phenom X3-8450e which has a total of 3 cores. But when i ran "sensors" on a terminal this is what i get. user@PC ~ $ sensors atk0110-acpi-0 Adapter: ACPI interface ...
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2answers
101 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 ...
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KVM reports strange CPU usage peaks (bash infinite recursion)

On a KVM machine running Fedora 20 I ran ulimit -s unlimited (this removes limit on stack size) and an experimental torturing testing script. All this script does is just infinite recursion: ...
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26 views

What does % utilization mean in htop if only 1 process can execute at a time?

I see that the htop command reports respective the % of utilisation of each CPU core and also that of the processes. We know that only 1 process can execute at a time in the CPU. How is it possible ...
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1answer
4 views

Setting running process affinity with taskset fails

I'm attempting to limit a process to a given number of CPU cores. According to the taskset man page and this documentation, the following should work: [fedora@dfarrell-opendaylight-cbench-devel ~]$ ...
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2answers
43 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?
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3answers
82 views

detect process eating cpu without: top, htop, ps?

I went thru a problem where I could only guess what process was eating the cpu. My cpu usage was about 80% for all cores at psensor. I tried htop, top and ps -A -o pcpu,pid,cmd --sort +pcpu (the ...
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28 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" ...
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57 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 ...
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1answer
126 views

Very high CPU load, but nothing significant in top

I'm running Ubuntu Linux 12.04.1, with VirtualMin 4.08.gpl GPL and 2 CPU cores. Pretty much all the time for the last few weeks, it's been running at well above load average of 5, usually up closer ...
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2answers
129 views

Does BIOS read directly the bootloader or load it into RAM?

I'm trying to understand the very first steps of the boot process. The CPU read the BIOS It reads a fixed address instruction It will jump to the first BIOS instructions address It will execute ...
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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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1answer
31 views

Check SSE3 support from bash?

Is there a way to check whether or not the current system supports SSE3 from a bash script? I'm currently writing an installer script, and the program in question has an alternate version that takes ...
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3answers
120 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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1answer
89 views

CPU Placement in KVM

I have a configuration of KVM guests where the cpu placement is configured as follows: <vcpu placement='static'>1</vcpu> Now since I don't have a cpuset specified I was reading libvirt ...
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1answer
99 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 ...
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2answers
200 views

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
46 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
57 views

How the network packets are transferred to the memory on linux?

Is there some command or tool for monitoring network packets and how those packets are handled by the memory and than proceeded to the CPU on linux platform? Using tcpdump I can capture many apache ...
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2answers
161 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
40 views

CPU and RAM monitorization by parent id

I'm trying to monitor the CPU and RAM usage (in % of total for example) of a given process wich may spawn several processes. The parent process is /bin/rscw so I get its pid by ppid_bl=$(ps -ef | ...
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37 views

Having an independent console to kill rogue process?

Sometimes a flash plugin starts using all the mem and CPU or an app is also behaving "naughtily" and my system starts to crawl until i finally get a terminal with htop up and kill the rogue process, ...
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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 ...
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1answer
79 views

What happens to the files when they are being decrypted?

I have the server's webroot directory mounted on a partition which is being protected with LUKS encryption. I want to know what happens to the files within when that partition is being decrypted. Does ...
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1answer
89 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 ...
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1answer
708 views

How can I monitor CPU usage by user?

I need to monitor CPU usage by users of two servers' (Ubuntu and CentOS). For example: user1 5% user2 10% ... Is there a tool similar to top or htop that can do that?
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1answer
163 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 ...
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7answers
1k views

cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options - 1. set up a cron-job or, 2. implement a loop with sleep in the script itself. Question: ...
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4answers
561 views

Why/how does “uptime” show CPU load >1?

I have a 1 core CPU installed on my PC. Sometimes, uptime shows load >1. How is this possible and what does this mean? EDIT: The values go up to 2.4
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1answer
102 views

Do processes in cgroups have to be set every boot? If so, how to persist them?

I was reading this answer to a question on setting limits for processes by using cgroups. The sample given sets limits for a process (in the example, sshd). In the answer, the PID of the process is ...
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1answer
63 views

Why my cpu spend so much time on system? [closed]

top - 08:58:42 up 20 days, 8:23, 1 user, load average: 67.17, 58.94, 62.75 Tasks: 630 total, 40 running, 524 sleeping, 0 stopped, 66 zombie Cpu(s): 57.3%us, 41.6%sy, 0.0%ni, 0.0%id, 0.0%wa, ...
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2answers
149 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 ...
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1answer
139 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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1answer
47 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.
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1answer
72 views

When speaking about cache size of a CPU, we only need the size of the cache at the furthest level [closed]

When speaking about cache size of a CPU, do we only need to know the size of the cache at the furthest level (such as at level 3, when the cache hierachy is 3-level)? Instead of the sum of all the ...
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24 views

Limit CPU/RAM usage per user? [duplicate]

I'm running game server applications on dedicated server that I have, but I want to be able to limit the CPU/RAM/etc usage on a per-user basis to make sure one of the servers doesn't eat up more ...
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2answers
372 views

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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1answer
101 views

Monitor CPU Registers

I'm looking for such tool, to see state of CPU registers, eax, ebx, ecx, edx. I've discovered cpuid: eax in eax ebx ecx edx 00000000 0000000d 756e6547 6c65746e 49656e69 00000001 ...
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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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1answer
300 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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1answer
118 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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2answers
83 views

Linux and CPU usage

What does it mean for a core to run at different loads in different moments? How does a 10% load differ from a 90% load? How is this number calculated, essentially?
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33 views

App consumes diferent %CPU if started at start-up or from prompt [closed]

I run an application in embedded system, and it needs to start at boot. However, I have a problem with it: when I execute it at boot (from rc.local script), it consumes nearly all the CPU, making the ...
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87 views

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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0answers
88 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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152 views

sar -P ALL command AIX 6.1

What is the meaning of - in the cpu column below? Is it average of all CPU cores? bash-3.00$ sar -P ALL 2 2 AIX tinapp1 1 6 00F6F78B4C00 11/27/13 System configuration: lcpu=4 mode=Capped 19:02:54 ...