psets on vmhost server to tie down vm guests

[Padraig Stafford]

scenario is as follows.

hpvm host server is dual core rx6600 (4 cpu's)

have 4 vm's running on it...i want to limit cpu uasge of vm's which i have done via hpvmmodify...if , say i limited it to 51% per vm, in theory no 2 vm's should hit same host cpu yes/no ?...I am wondering now should I not bother limiting cpu via hpvmmodify and just assign a hos cpu to each vm via psets ?

any previous experience or educated retorts gladly excepted

[Torsten.]

As far as I understand your question:

You don't limit a CPU for a HPVM, but you guarantee a minimum CPU power to a HPVM.

If you set a HPVM to an entitlement of 10% and another to 20%, they get always this power as a minimum.

If they need more, they can get more if needed and available, but never less.

Read more in the chapter

"3.1.4 Entitlement" in the "HP Integrity Virtual Machines -
Installation, Configuration, and
Administration" Guide

Quote:

"When the virtual machine starts, the VM Host ensures that sufficient processing power is available
for every running virtual machine to receive its entitlement. For virtual machines with multiple
virtual CPUs, the entitlement is guaranteed on each vCPU in the virtual machine's configuration.
For example, if a virtual machine has four vCPUs, and the entitlement is set at 12%, the VM Host
ensures that the equivalent of at least 48% of one physical CPU is available to that virtual machine."

[Tim Nelson]

As Torsten mentetioned. I also do not see an hpvmcreate or hpvmmodify option to restrict CPU usage, only to ensure a minimum.

If you start adding external pset control configurations into the vm host how will that effect the IVM functionality ?

Why do you want to limit a vm guest ? If you want to hard define what runs on which CPU and who can an cannot share then vPars might be a better solution. The idea of IVM is to granularly share all the resources vs hard per resource allocations.

[melvyn burnard]

you should not use psets to control the hpvm processes.
You are asking for problems

[Padraig Stafford]

Appreciate the help guys !

if i set hpvm to 51% and 51% (dif eg to your 10 and 20% torsten) I would have thought they can never get more power or even be on the same cpu as the sum of their parts is greater than 100%..I appreciate the fact that 51% means that is the minimum power they are guarnteed which I have no problem with.fact is I set them to 51% so as no vm would overload an individual cpu.

Now I notice on monitoring a top session , the hpvmapp process for each vm can jump from cpu to cpu verloading one cpu leaving no load on another !

My next question is to burnard...can you explain and maybe backup why I shouldn't use psets to control vm's host cpu usage !

[Torsten.]

I'm quite sure if you set both HPVM to 51%, the second won't start because of insufficient resources.

[Tim Nelson]

Another note..

If you drill into the hpvmapp process with glance and then view the threads you will notice that the threads for the virtual host are spread accross many CPUs.

After seeing this the attempt to restrict may be fruitless.