Missing CPU Cores in Oracle VM Server

MattBoston

We just started using Oracle VM Server and have it installed on a HP Proliant DL380G9. It has 2x processors with 8 cores/16 threads each. So there should be a total of 16 cores/32 threads. If I view the CPU info in iLo it matches and if I look at the server in Oracle VM Manager under Server Pools -> MainPool -> ovms01 -> Info it says Processors = 32. If I view the CPUs for the server, it lists 32x Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz each with 20480 L2 Cache. xm info shows 32 cpus. If I ssh into the ovms server and run top, it only shows processors 0-19. But if I look under the Control Domains, it only says there are 20 processors. How can I take advantage of all the cores/threads?

[[email protected] ~]# xm info
host                   : dcovms01.frtservices.com
release                : 4.1.12-124.21.1.el6uek.x86_64
version                : #2 SMP Tue Nov 6 13:31:13 PST 2018
machine                : x86_64
nr_cpus                : 32
nr_nodes               : 2
cores_per_socket       : 8
threads_per_core       : 2
cpu_mhz                : 2097
hw_caps                : bfebfbff:2c100800:00000000:01707f00:77fefbff:00000000:00000121:021cbfbb
virt_caps              : hvm hvm_directio
total_memory           : 262014
free_memory            : 5692
free_cpus              : 0
xen_major              : 4
xen_minor              : 4
xen_extra              : .4OVM
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : 
xen_commandline        : placeholder dom0_mem=max:6144M allowsuperpage dom0_vcpus_pin dom0_max_vcpus=20 no-real-mode edd=off
cc_compiler            : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18.0.7)
cc_compile_by          : mockbuild
cc_compile_domain      : us.oracle.com
cc_compile_date        : Fri Nov 16 14:44:18 PST 2018
xend_config_format     : 4

Nik

Hi.

It's not answer, but another question:

What reason at 2021 start new installation of OVM, when Oracle stop develop this product and available only extended support ?

What I see at output:

nr_cpus                : 32
nr_nodes               : 2
cores_per_socket       : 8
threads_per_core       : 2

So System correctly detect hardware.

xen_commandline        : placeholder dom0_mem=max:6144M allowsuperpage dom0_vcpus_pin dom0_max_vcpus=20 no-real-mode edd=off

So it's look like some configuration limit for some performance reason.

https://docs.oracle.com/html/E50247_08/vmiug-upgrade-server-final-steps-edit-boot-params.html

Regards,

Nik.

MattBoston

We're required to use it to keep in compliance with the Oracle DB licensing.

Here's what's in out grub file, so it looks like what you posted and what's in the doc you sent. I've read through the doc (and a few others) that reference dom0_max_vcpus and dom0_vcpus_pin and it doesn't say what it should be changed to if we modify it. If we have 32 cores, should we change this to 32? The issue we're trying to figure out is we're seeing poor performance from the single vm that's on this server.

multiboot2      /xen.mb.efi placeholder dom0_mem=max:6144M allowsuperpage dom0_vcpus_pin dom0_max_vcpus=20  ${xen_rm_opts}

Nik

Hi.

1. Read current doc about partition for Oracle DB. OLVM (KVM-based virtualization from Oracle) also supported.

2. dom0_max_vcpus limit the number of vcpu that can be assigned to contro domain (dom0). It is spesial domain, not for user application.

https://community.oracle.com/tech/apps-infra/discussion/4174052/changing-the-memory-size-of-the-management-domain-dom0-by-editing-etc-default-grub

You should create guest domain and check number of available cpu at guest domain.

Regards,

Nik.