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Hi,

I am working on a AIX 5 system with three processors and we would like
to limit the maximum number of processors a multithread application is
allowed to use to two.

Is this possible at application level, or is it possible at user level
to limit the number of processors that the application or user is going
to use.

Thanks in advance,

jmartin schrieb:

> Hi,
>
> I am working on a AIX 5 system with three processors and we would like
> to limit the maximum number of processors a multithread application is
> allowed to use to two.
>
> Is this possible at application level, or is it possible at user level
> to limit the number of processors that the application or user is going
> to use.

man wlm ( Work Load Manager )

The wsm has a nice interface for the work load manager ( wlm )

hth
Hajo

Hi,

I have checked the WLM documentation and it seems that you can limit
the percentage of CPU that an application or user can use, but not the
number of processors that it can use. I have 3 processors but
specifying 66% or CPU usage doesn't assure that you are using 2
processors, I think.

Is there a way to limit the processors an application can use?

There is an application: LoadLeveler, anybody knows if it can be
configured to limit the number of processors an application or user can
use?

Thanks in advance,

Hajo Ehlers ha escrito:

> jmartin schrieb:
>
> > Hi,
> >
> > I am working on a AIX 5 system with three processors and we would like
> > to limit the maximum number of processors a multithread application is
> > allowed to use to two.
> >
> > Is this possible at application level, or is it possible at user level
> > to limit the number of processors that the application or user is going
> > to use.
>
> man wlm ( Work Load Manager )
>
> The wsm has a nice interface for the work load manager ( wlm )
>
> hth
> Hajo

jmartin wrote:
> Hi,
>
> I have checked the WLM documentation and it seems that you can limit
> the percentage of CPU that an application or user can use, but not the
> number of processors that it can use. I have 3 processors but
> specifying 66% or CPU usage doesn't assure that you are using 2
> processors, I think.
>
> Is there a way to limit the processors an application can use?
>
> There is an application: LoadLeveler, anybody knows if it can be
> configured to limit the number of processors an application or user can
> use?
>
> Thanks in advance,
>
> Hajo Ehlers ha escrito:
>
> > jmartin schrieb:
> >
> > > Hi,
> > >
> > > I am working on a AIX 5 system with three processors and we would like
> > > to limit the maximum number of processors a multithread application is
> > > allowed to use to two.
> > >
> > > Is this possible at application level, or is it possible at user level
> > > to limit the number of processors that the application or user is going
> > > to use.
> >
> > man wlm ( Work Load Manager )
> >
> > The wsm has a nice interface for the work load manager ( wlm )
> >
> > hth
> > Hajo

Hi,

Depending on the AIX version and hardware you can disable a processor
completely.

Use the following procedure:

WARNING! The CPU can only be reenabled by rebooting!

List available processors:

$ bindprocessor -q
The available processors are: 0 1 2 3 4 5

Then use cpu_deallocate to switch one off:
cpu_deallocate requires a logical CPU number
Usage: cpu_deallocate logical_CPU_id [-P]

$ cpu_deallocate 5

Then enter the following:

$ chdev -a cpuguard=enable -l sys0
sys0 changed

And now list processors again:

$ bindprocessor -q
The available processors are: 0 1 2 3 4


I don't know what the -P flag does, so I suggest not using it (because
perhaps it means 'permanent'?)!!

Scott

Hi,

I don't want to deallocate a processor because that is for all the
applications, and we want to use them all for most applications like
oracle. The problem is that we have a licence in one application for
two processors and the machine has 3. We want to limit this only
application to two processors. Is that possible or we need to upgrade
the licence to three processors as the last chance?

Thanks in advance,

One (not so clean) way is to bind the individual threads (of your
multithreaded application) to the processor you want to use. For
example, if your application has 4 threads, you can bind 2 threads to
one processor, and other 2 to other processor. This way you can limit
your application to only those two processors.

-KC

jmartin schrieb:

> Hi,
>
> I don't want to deallocate a processor because that is for all the
> applications, and we want to use them all for most applications like
> oracle. The problem is that we have a licence in one application for
> two processors and the machine has 3. We want to limit this only
> application to two processors. Is that possible or we need to upgrade
> the licence to three processors as the last chance?

Its not your last change. You should ask the software vendor that they
fix their software , so that the software uses only 2 Processors even
if a system has more.

In case the application can be run on 1 processor you might use the
bindprocessor command.
see
$ man bindprocessor
for details but it does will not help if the application will check for
the amount of processors.

In case you are running at least AIX 5.2 in an LPAR you just might
remove a CPU before you start your APP and then adding it back after
the application starts. But its more or less a work-around againt a
badly behaving application

hth
Hajo




b
Meaning its more less a software problem not a

Use Workload Manager and the resource sets feature that will let you
move the processes to just 2 CPUs.
This will also let your processes move between the two CPUs i.e. load
balance.

Good starting whitepaper on WLM at
http://www-128.ibm.com/developerwork...tical_WLM.html

Hi and thanks,

As you say the resource sets feature allows to assign two CPUs to a
process.
The link you provide is very interesting, and points to where to see
things in more detail.

I think the problem is solved,

Greetings,

Nigel ha escrito:

> Use Workload Manager and the resource sets feature that will let you
> move the processes to just 2 CPUs.
> This will also let your processes move between the two CPUs i.e. load
> balance.
>
> Good starting whitepaper on WLM at
> http://www-128.ibm.com/developerwork...tical_WLM.html

On Thu, 22 Jun 2006 16:17:55 UTC, "jmartin"
<jorge.jose.martin@cgi.com> wrote:
>
> I don't want to deallocate a processor because that is for all the
> applications, and we want to use them all for most applications like
> oracle. The problem is that we have a licence in one application for
> two processors and the machine has 3. We want to limit this only
> application to two processors. Is that possible or we need to upgrade
> the licence to three processors as the last chance?

Ah, *licenses*. In my humble experience, manufacturers don't give a
toss about the number of processors you actually use. If your box has
64 processors, you will need 64 licenses, even if you are using it
only on one little u-LPAR that uses one tenth of a processor. So even
if you can guarantee that the app will only use two processors, that
doesn't help your license any.


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