Home » Mailing lists » Users » Measuring and Adjusting CPU utilization
| Measuring and Adjusting CPU utilization [message #3602] |
Tue, 06 June 2006 18:03  |
Pradeep Padala
Messages: 18
Registered: June 2006
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Junior Member |
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Hi,
I am trying to measure the CPU utlilization of the VZ containers, and change
the cpu share dynamically. I have poured over most of the documentation, and
looked at the code as well, and it seems like there's no utility that can
directly show the current CPU utilization of a container (some thing like
30% of CPU). A search on the user list got me a message, where someone
suggested using loadavg. However, It seems like the loadavg is not showing
the proper utilization (or showing the total CPU utilization). This is what
I am doing.
I setup a container with 1000 units limit (total CPU units: ~10000). I wrote
a small do {; }while(1); loop and ran it in the container, now I do cat
/proc/loadavg in both the container and on the host node. Since, the
container is only using 1000 units, I should see something like 100% loadavg
in the container, and 10% loadavg in the hostnode. But, I see 100% at both
places. Am I doing something wrong? How do I get the current cpu utilization
of a container?
Thanks,
--
Pradeep Padala
http://ppadala.blogspot.com
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| Re: Measuring and Adjusting CPU utilization [message #3603 is a reply to message #3602] |
Tue, 06 June 2006 23:17  |
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Looks like you misunderstand the concept of cpuunits. cpuunits is not a
hard limit, but just a suggestion, and a CPU time is shared
proportionally to the values given. So, if you will have 9 VEs and the
host system with cpuunits set to 1000 for all of them, and run the loop
in all of them, each VE will use 10% of the CPU time.
In case you will stop the loop running in 5 VEs so there will be 4 such
VEs (plus the host system) left, each of them will use 20% of the CPU.
So, all the CPU time is distributed between VEs which will need it,
according with their proportional cpuunits.
More to say, the concept of "total CPU units" is purely fiction, and is
here just for the convenience. People do want to set CPU units is terms
of processor's megaherts, and this is what cpuunits does. But in fact it
is not a megaherts but just a relative weights. I.e. all the cpuunits
values are relative to each other, it doesn't matter what the actual
numbers are -- what matters is a number given to a VE in relation to the
sum of all cpuweights (which is expressed as "total CPU units" just for
the convenience).
So, cpuunits, if you do not oversell them, are a CPU guarantee, not a
limit. If you want CPU limit -- use cpulimit parameter.
Pradeep Padala wrote:
> Hi,
>
> I am trying to measure the CPU utlilization of the VZ containers, and
> change the cpu share dynamically. I have poured over most of the
> documentation, and looked at the code as well, and it seems like
> there's no utility that can directly show the current CPU utilization
> of a container (some thing like 30% of CPU). A search on the user list
> got me a message, where someone suggested using loadavg. However, It
> seems like the loadavg is not showing the proper utilization (or
> showing the total CPU utilization). This is what I am doing.
>
> I setup a container with 1000 units limit (total CPU units: ~10000). I
> wrote a small do {; }while(1); loop and ran it in the container, now I
> do cat /proc/loadavg in both the container and on the host node.
> Since, the container is only using 1000 units, I should see something
> like 100% loadavg in the container, and 10% loadavg in the hostnode.
> But, I see 100% at both places. Am I doing something wrong? How do I
> get the current cpu utilization of a container?
>
> Thanks,
> --
> Pradeep Padala
> http://ppadala.blogspot.com
>
> ------------------------------------------------------------ ------------
>
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| Re: Measuring and Adjusting CPU utilization [message #3604 is a reply to message #3603] |
Tue, 06 June 2006 23:27 |
Pradeep Padala
Messages: 18
Registered: June 2006
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Junior Member |
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Thanks for the explanation, but I DID use the --cpulimit parameter.
I set the limit to 1000 units, I run a while(1) loop, and I see a 100%
loadavg on the host node. Shouldn't it be somewhere around 10% ?
Pradeep
On 6/6/06, Kir Kolyshkin <kir@openvz.org> wrote:
>
> Looks like you misunderstand the concept of cpuunits. cpuunits is not a
> hard limit, but just a suggestion, and a CPU time is shared
> proportionally to the values given. So, if you will have 9 VEs and the
> host system with cpuunits set to 1000 for all of them, and run the loop
> in all of them, each VE will use 10% of the CPU time.
>
> In case you will stop the loop running in 5 VEs so there will be 4 such
> VEs (plus the host system) left, each of them will use 20% of the CPU.
> So, all the CPU time is distributed between VEs which will need it,
> according with their proportional cpuunits.
>
> More to say, the concept of "total CPU units" is purely fiction, and is
> here just for the convenience. People do want to set CPU units is terms
> of processor's megaherts, and this is what cpuunits does. But in fact it
> is not a megaherts but just a relative weights. I.e. all the cpuunits
> values are relative to each other, it doesn't matter what the actual
> numbers are -- what matters is a number given to a VE in relation to the
> sum of all cpuweights (which is expressed as "total CPU units" just for
> the convenience).
>
> So, cpuunits, if you do not oversell them, are a CPU guarantee, not a
> limit. If you want CPU limit -- use cpulimit parameter.
>
> Pradeep Padala wrote:
>
> > Hi,
> >
> > I am trying to measure the CPU utlilization of the VZ containers, and
> > change the cpu share dynamically. I have poured over most of the
> > documentation, and looked at the code as well, and it seems like
> > there's no utility that can directly show the current CPU utilization
> > of a container (some thing like 30% of CPU). A search on the user list
> > got me a message, where someone suggested using loadavg. However, It
> > seems like the loadavg is not showing the proper utilization (or
> > showing the total CPU utilization). This is what I am doing.
> >
> > I setup a container with 1000 units limit (total CPU units: ~10000). I
> > wrote a small do {; }while(1); loop and ran it in the container, now I
> > do cat /proc/loadavg in both the container and on the host node.
> > Since, the container is only using 1000 units, I should see something
> > like 100% loadavg in the container, and 10% loadavg in the hostnode.
> > But, I see 100% at both places. Am I doing something wrong? How do I
> > get the current cpu utilization of a container?
> >
> > Thanks,
> > --
> > Pradeep Padala
> > http://ppadala.blogspot.com
> >
> > ------------------------------------------------------------ ------------
> >
--
Pradeep Padala
http://ppadala.blogspot.com
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| Re: Measuring and Adjusting CPU utilization [message #3605 is a reply to message #3604] |
Wed, 07 June 2006 00:12 |
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CPU limit is in per cent units. I.e. if your server has a single CPU,
use --cpulimit 10 to limit a VE to 10% of the CPU.
On a two-way SMP box max. value of cpulimit is 200. Say, if you want a
VE to use no more than one CPUs, use --cpulimit 100.
Pradeep Padala wrote:
> Thanks for the explanation, but I DID use the --cpulimit parameter.
>
> I set the limit to 1000 units, I run a while(1) loop, and I see a 100%
> loadavg on the host node. Shouldn't it be somewhere around 10% ?
>
> Pradeep
>
> On 6/6/06, *Kir Kolyshkin* <kir@openvz.org <mailto:kir@openvz.org>>
> wrote:
>
> Looks like you misunderstand the concept of cpuunits. cpuunits is
> not a
> hard limit, but just a suggestion, and a CPU time is shared
> proportionally to the values given. So, if you will have 9 VEs and the
> host system with cpuunits set to 1000 for all of them, and run the
> loop
> in all of them, each VE will use 10% of the CPU time.
>
> In case you will stop the loop running in 5 VEs so there will be 4
> such
> VEs (plus the host system) left, each of them will use 20% of the CPU.
> So, all the CPU time is distributed between VEs which will need it,
> according with their proportional cpuunits.
>
> More to say, the concept of "total CPU units" is purely fiction,
> and is
> here just for the convenience. People do want to set CPU units is
> terms
> of processor's megaherts, and this is what cpuunits does. But in
> fact it
> is not a megaherts but just a relative weights. I.e. all the cpuunits
> values are relative to each other, it doesn't matter what the actual
> numbers are -- what matters is a number given to a VE in relation
> to the
> sum of all cpuweights (which is expressed as "total CPU units"
> just for
> the convenience).
>
> So, cpuunits, if you do not oversell them, are a CPU guarantee, not a
> limit. If you want CPU limit -- use cpulimit parameter.
>
> Pradeep Padala wrote:
>
> > Hi,
> >
> > I am trying to measure the CPU utlilization of the VZ
> containers, and
> > change the cpu share dynamically. I have poured over most of the
> > documentation, and looked at the code as well, and it seems like
> > there's no utility that can directly show the current CPU
> utilization
> > of a container (some thing like 30% of CPU). A search on the
> user list
> > got me a message, where someone suggested using loadavg.
> However, It
> > seems like the loadavg is not showing the proper utilization (or
> > showing the total CPU utilization). This is what I am doing.
> >
> > I setup a container with 1000 units limit (total CPU units:
> ~10000). I
> > wrote a small do {; }while(1); loop and ran it in the container,
> now I
> > do cat /proc/loadavg in both the container and on the host node.
> > Since, the container is only using 1000 units, I should see
> something
> > like 100% loadavg in the container, and 10% loadavg in the hostnode.
> > But, I see 100% at both places. Am I doing something wrong? How do I
> > get the current cpu utilization of a container?
> >
> > Thanks,
> > --
> > Pradeep Padala
> > http://ppadala.blogspot.com
> >
> > ------------------------------------------------------------ ------------
> >
> >_______________________________________________
> >Users mailing list
> >Users@openvz.org <mailto:Users@openvz.org>
> >https://openvz.org/mailman/listinfo/users
> <https://openvz.org/mailman/listinfo/users>
> >
> >
>
> _______________________________________________
> Users mailing list
> Users@openvz.org <mailto:Users@openvz.org>
> https://openvz.org/mailman/listinfo/users
> <https://openvz.org/mailman/listinfo/users>
>
>
>
>
> --
> Pradeep Padala
> http://ppadala.blogspot.com
>
> ------------------------------------------------------------ ------------
>
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| Re: Measuring and Adjusting CPU utilization [message #3607 is a reply to message #3605] |
Wed, 07 June 2006 00:33 |
Pradeep Padala
Messages: 18
Registered: June 2006
|
Junior Member |
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On 6/6/06, Kir Kolyshkin <kir@openvz.org> wrote:
>
> CPU limit is in per cent units. I.e. if your server has a single CPU,
> use --cpulimit 10 to limit a VE to 10% of the CPU.
>
> On a two-way SMP box max. value of cpulimit is 200. Say, if you want a
> VE to use no more than one CPUs, use --cpulimit 100.
Thanks ! This solved the problem. However, I still see the loadavg at 100%
(got from cat /proc/loadavg), but if I run top and see the CPU% for the one
particular application (while(1) loop), it is limited to 10% CPU.
I can add up the CPU% for all the processes running in the container, and
can get the current % utilization of the container. Is there a better way to
do this?
Pradeep
Pradeep Padala wrote:
>
> > Thanks for the explanation, but I DID use the --cpulimit parameter.
> >
> > I set the limit to 1000 units, I run a while(1) loop, and I see a 100%
> > loadavg on the host node. Shouldn't it be somewhere around 10% ?
> >
> > Pradeep
> >
> > On 6/6/06, *Kir Kolyshkin* <kir@openvz.org <mailto:kir@openvz.org>>
> > wrote:
> >
> > Looks like you misunderstand the concept of cpuunits. cpuunits is
> > not a
> > hard limit, but just a suggestion, and a CPU time is shared
> > proportionally to the values given. So, if you will have 9 VEs and
> the
> > host system with cpuunits set to 1000 for all of them, and run the
> > loop
> > in all of them, each VE will use 10% of the CPU time.
> >
> > In case you will stop the loop running in 5 VEs so there will be 4
> > such
> > VEs (plus the host system) left, each of them will use 20% of the
> CPU.
> > So, all the CPU time is distributed between VEs which will need it,
> > according with their proportional cpuunits.
> >
> > More to say, the concept of "total CPU units" is purely fiction,
> > and is
> > here just for the convenience. People do want to set CPU units is
> > terms
> > of processor's megaherts, and this is what cpuunits does. But in
> > fact it
> > is not a megaherts but just a relative weights. I.e. all the
> cpuunits
> > values are relative to each other, it doesn't matter what the actual
> > numbers are -- what matters is a number given to a VE in relation
> > to the
> > sum of all cpuweights (which is expressed as "total CPU units"
> > just for
> > the convenience).
> >
> > So, cpuunits, if you do not oversell them, are a CPU guarantee, not
> a
> > limit. If you want CPU limit -- use cpulimit parameter.
> >
> > Pradeep Padala wrote:
> >
> > > Hi,
> > >
> > > I am trying to measure the CPU utlilization of the VZ
> > containers, and
> > > change the cpu share dynamically. I have poured over most of the
> > > documentation, and looked at the code as well, and it seems like
> > > there's no utility that can directly show the current CPU
> > utilization
> > > of a container (some thing like 30% of CPU). A search on the
> > user list
> > > got me a message, where someone suggested using loadavg.
> > However, It
> > > seems like the loadavg is not showing the proper utilization (or
> > > showing the total CPU utilization). This is what I am doing.
> > >
> > > I setup a container with 1000 units limit (total CPU units:
> > ~10000). I
> > > wrote a small do {; }while(1); loop and ran it in the container,
> > now I
> > > do cat /proc/loadavg in both the container and on the host node.
> > > Since, the container is only using 1000 units, I should see
> > something
> > > like 100% loadavg in the container, and 10% loadavg in the
> hostnode.
> > > But, I see 100% at both places. Am I doing something wrong? How do
> I
> > > get the current cpu utilization of a container?
> > >
> > > Thanks,
>
>
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| Re: Measuring and Adjusting CPU utilization [message #3615 is a reply to message #3607] |
Wed, 07 June 2006 08:20 |
dev
Messages: 1693
Registered: September 2005
Location: Moscow
|
Senior Member |
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> Thanks ! This solved the problem. However, I still see the loadavg at
> 100% (got from cat /proc/loadavg), but if I run top and see the CPU% for
> the one particular application (while(1) loop), it is limited to 10% CPU.
This is also correct, since load average means 'average number of
processes in running + uninterruptible state'. Since you busy loop is
constantly in running state, it is accounted as 1.0 in loadavg.
> I can add up the CPU% for all the processes running in the container,
> and can get the current % utilization of the container. Is there a
> better way to do this?
Sorry, didn't got what you mean... Probably you ask how to calculate the
amount of CPU being consumed by VPS in %?
To do so, you need to monitor /proc/vz/vestat file.
http://forum.openvz.org/index.php?t=msg&goto=2790&&a mp;srch=vestat#msg_2790
Thanks,
Kirill
> Pradeep
>
>
> Pradeep Padala wrote:
>
> > Thanks for the explanation, but I DID use the --cpulimit parameter.
> >
> > I set the limit to 1000 units, I run a while(1) loop, and I see a
> 100%
> > loadavg on the host node. Shouldn't it be somewhere around 10% ?
> >
> > Pradeep
> >
> > On 6/6/06, *Kir Kolyshkin* <kir@openvz.org
> <mailto:kir@openvz.org> <mailto:kir@openvz.org <mailto:kir@openvz.org>>>
> > wrote:
> >
> > Looks like you misunderstand the concept of cpuunits.
> cpuunits is
> > not a
> > hard limit, but just a suggestion, and a CPU time is shared
> > proportionally to the values given. So, if you will have 9
> VEs and the
> > host system with cpuunits set to 1000 for all of them, and
> run the
> > loop
> > in all of them, each VE will use 10% of the CPU time.
> >
> > In case you will stop the loop running in 5 VEs so there will
> be 4
> > such
> > VEs (plus the host system) left, each of them will use 20% of
> the CPU.
> > So, all the CPU time is distributed between VEs which will
> need it,
> > according with their proportional cpuunits.
> >
> > More to say, the concept of "total CPU units" is purely fiction,
> > and is
> > here just for the convenience. People do want to set CPU units is
> > terms
> > of processor's megaherts, and this is what cpuunits does. But in
> > fact it
> > is not a megaherts but just a relative weights. I.e. all the
> cpuunits
> > values are relative to each other, it doesn't matter what the
> actual
> > numbers are -- what matters is a number given to a VE in relation
> > to the
> > sum of all cpuweights (which is expressed as "total CPU units"
> > just for
> > the convenience).
> >
> > So, cpuunits, if you do not oversell them, are a CPU
> guarantee, not a
> > limit. If you want CPU limit -- use cpulimit parameter.
> >
> > Pradeep Padala wrote:
> >
> > > Hi,
> > >
> > > I am trying to measure the CPU utlilization of the VZ
> > containers, and
> > > change the cpu share dynamically. I have poured over most
> of the
> > > documentation, and looked at the code as well, and it seems
> like
> > > there's no utility that can directly show the current CPU
> > utilization
> > > of a container (some thing like 30% of CPU). A search on the
> > user list
> > > got me a message, where someone suggested using loadavg.
> > However, It
> > > seems like the loadavg is not showing the proper
> utilization (or
> > > showing the total CPU utilization). This is what I am doing.
> > >
> > > I setup a container with 1000 units limit (total CPU units:
> > ~10000). I
> > > wrote a small do {; }while(1); loop and ran it in the
> container,
> > now I
> > > do cat /proc/loadavg in both the container and on the host
> node.
> > > Since, the container is only using 1000 units, I should see
> > something
> > > like 100% loadavg in the container, and 10% loadavg in the
> hostnode.
> > > But, I see 100% at both places. Am I doing something wrong?
> How do I
> > > get the current cpu utilization of a container?
> > >
> > > Thanks,
>
>
> ------------------------------------------------------------ ------------
>
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