NUMA has been working on Xen on RHEL 5 for quite some time. The problem
is, you cannot get the information from Dom0 because it does not control
it - the hypervisor does. So what you need to do to enable NUMA on the
hypervisor is to add "numa=on" to the kernel command line (to the Xen
hypervisor) like this:
title Red Hat Enterprise Linux Server (2.6.18-194.8.1.el5xen)
root (hd0,0)
kernel /xen.gz-2.6.18-194.8.1.el5 dom0_mem=786432
crashkernel=128M@64M com1=9600,8n1 dom0_max_vcpus=3 numa=on
module /vmlinuz-2.6.18-194.8.1.el5xen ro root=/dev/vg00/lv_root
console=tty0 console=ttyS0,9600n8 iommu="amd" single quiet
module /initrd-2.6.18-194.8.1.el5xen.img
I can confirm that this does change the behaviour / performance of VMs.
Regards,
Morgan
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Rich Graves
Sent: Friday, March 18, 2011 3:23 PM
To: [email protected]
Subject: [rhelv5-list] Xen NUMA status/best practices in RHEL 5.6
The ancient bugzilla 219951, resolved, complained about terrible Xen
performance on NUMA systems. What's the current status as of 5.6?
How best to size VMs/VCPUs to match NUMA architecture?
Currently numactl --show tells me "No NUMA support available on this
system" on a dual-6-core X5680 with 96GB RAM (Dell R710). Surely this is
wrong.
Is there any reason to believe that performance of large VMs (> 32GB
RAM) on above hardware (mpathed qle2462 to storage) would be
significantly better under KVM than under Xen?
--
Rich Graves http://claimid.com/rcgraves
Carleton.edu Sr UNIX and Security Admin
CMC135: 507-222-7079 Cell: 952-292-6529
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