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*SOLVED* Limit the VE number of processor usage [message #14028]

Tue, 12 June 2007 11:12

jmslkn
Messages: 19
Registered: June 2007

Junior Member

Is there any way to limit the number of processor associated to a VE? Eg.: processor1 used by VE101 50%, VE102 50%; processor2 used by ve110 100%.

Regards.
J.

[Updated on: Thu, 14 June 2007 09:54] by Moderator

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Re: Limit the VE number of processor usage [message #14030 is a reply to message #14028]

Tue, 12 June 2007 11:42

ugob
Messages: 271
Registered: March 2007

Senior Member

[root@server dump]# vzcpucheck
Current CPU utilization: 278775
Power of the node: 445874

[root@server dump]# grep CPU /etc/vz/conf/101.conf
CPUUNITS="51125"

Please read the manual before asking questions:
http://download.openvz.org/doc/OpenVZ-Users-Guide.pdf

Please have a look at the wiki before asking questions:
http://wiki.openvz.org/Main_Page

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Re: Limit the VE number of processor usage [message #14031 is a reply to message #14028]

Tue, 12 June 2007 11:51

rickb
Messages: 368
Registered: October 2006

Senior Member

On a SMP kernel, this is not possible.

OpenVZ distributes/limits according to cputime only. Openvz does not allow you to control which cpu the cputime is spent on.

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Common Terms I post with: http://wiki.openvz.org/Category:Definitions

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Re: Limit the VE number of processor usage [message #14032 is a reply to message #14031]

Tue, 12 June 2007 12:07

jmslkn
Messages: 19
Registered: June 2007

Junior Member

Thanks for the answer. However I have found a standard tool (taskset) which can modify the processor affinity mask for a task. [1] [2]

It is possible to change the VE init process CPU affinity mask? As far as I know the affinity mask inherinted from the parent process. The OpenVZ cputime counter prepared for these kinds of affinity modifications?

Thanks,
J.

[1] http://www.linuxcommand.org/man_pages/taskset1.html
[2] http://en.wikipedia.org/wiki/Affinity_mask

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Re: Limit the VE number of processor usage [message #14033 is a reply to message #14032]

Tue, 12 June 2007 12:14

rickb
Messages: 368
Registered: October 2006

Senior Member

In that case, yes you can request a set of processes to be restricted to a specific set of cpus. I am not sure how this will effect performance but I am assuming you are not looking for an overall gain, more like extreme fairness control. Download the openvz patch and towards the beginning there is a few paragraphs on the 2nd level cpu scheduler. This will illustrate how openvz selects a process and decides which physical cpu it gets run on. The final choice is made with the normal scheduler, which is where processor affinity would take effect.

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Common Terms I post with: http://wiki.openvz.org/Category:Definitions

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Re: Limit the VE number of processor usage [message #14077 is a reply to message #14028]

Thu, 14 June 2007 09:53

Vasily Tarasov
Messages: 1345
Registered: January 2006

Senior Member

Hello,

you can set the number of available CPUs in VE by --cpus command:

# vzctl set <veid> --cpus 1

HTH,
Vasily.

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Re: Limit the VE number of processor usage [message #14090 is a reply to message #14077]

Thu, 14 June 2007 14:25

rickb
Messages: 368
Registered: October 2006

Senior Member

yes, I believe he knew about that as its in the man page. what he wants to do is bind VEs to specific CPU(s). solaris supports this, I don't really know how useful it is unless you have some massive mainframe where you want better isolation.

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Common Terms I post with: http://wiki.openvz.org/Category:Definitions

UBC. Learn it, love it, live it: http://wiki.openvz.org/Proc/user_beancounters

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