The cpu tag has no wiki summary.
24
votes
2answers
7k views
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 ...
3
votes
3answers
320 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.
6
votes
2answers
637 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 ...
3
votes
1answer
410 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 ...
2
votes
1answer
797 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 ...
13
votes
2answers
445 views
Is it possible to limit how much CPU power a process can take?
I'm wondering, is there way to tell a process how much processor power it can take?
The problem is I'm converting video with Arista (video converter) and I'm annoyed by the fan running like crazy, ...
5
votes
2answers
868 views
VirtualBox guest: 16 CPUs detected but only 1 online
I am running VirtualBox (using the Qiime image http://qiime.org/install/virtual_box.html)
The physical hardware is a 32 core machine. The virtual machine in VirtualBox has been given 16 cores.
When ...
2
votes
1answer
155 views
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 ...
20
votes
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 ...
3
votes
2answers
243 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 ...
3
votes
2answers
352 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?
8
votes
2answers
527 views
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
...
1
vote
1answer
171 views
Make effective the changes in CPU governor plugin
I'm using Debian Testing + Xfce. I added to my panel the plugin the handle the CPU governor.
My problem is that the setting that I do on the plugin interface are not made effective. Maybe because I'm ...
1
vote
1answer
715 views
How to increase Xen guest CPU utilization?
My Xen dom0 is a Gentoo x64 pvops. I boot my guest Gentoo, in PV mode, system with the same kernel my dom0 uses. When I emerge in the guest system, building a CPP package, I am experiencing low CPU ...
7
votes
2answers
335 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? ...
12
votes
5answers
540 views
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 ...
3
votes
2answers
607 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?
2
votes
1answer
503 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 ...
8
votes
3answers
2k views
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 ...
0
votes
1answer
272 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.
1
vote
4answers
502 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 ...
3
votes
2answers
536 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 ...
6
votes
1answer
921 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 ...
1
vote
2answers
216 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 ...
1
vote
0answers
92 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 ...
1
vote
1answer
266 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 ...
2
votes
3answers
2k 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 ...
4
votes
2answers
1k 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
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 ...
5
votes
1answer
313 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?
2
votes
3answers
296 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
277 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 ...
1
vote
2answers
995 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 ...
2
votes
2answers
240 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.?
3
votes
1answer
494 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 ...
5
votes
2answers
2k views
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 ...
1
vote
1answer
346 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 ...
7
votes
2answers
7k views
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 ...
0
votes
2answers
377 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 ...
4
votes
3answers
2k 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
5
votes
2answers
2k 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 ...
15
votes
1answer
16k views
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, ...
11
votes
3answers
1k views
How can I have 400% CPU occupied on 2 cores
I understand that Σ(%CPU) ≤ logicalcores*(1+ε) (where ε is measure and rounding error). But, how can I have on a 2 core system 2 different processes, each taking 200% of CPU (as measured by htop)?
...
5
votes
1answer
3k 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 ...
4
votes
2answers
430 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 ...
3
votes
2answers
760 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 ...
2
votes
2answers
321 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 : ...
3
votes
1answer
753 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 ...
1
vote
1answer
612 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 ...
1
vote
1answer
266 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( ...
