How to setup low CPU priority domU

Jan Hejl
Tue, 24 Sep 2013 07:57:56 -0000

Hello everyone,

i would like to use one of my domU with all 32 hardware cores but with
lower priority (something like nice 10), but setting cpu weight seems to
be someway unstable.

Dom0 is Gentoo with Xen 4.3.0, 2 AMD Opetrons 6274 (32 cores), 64GB of
memory, but dom0 runs on 16 cores and 32GB of memory. Hosts 5 linux
domUs with similiar configs, each from 2 to 4 cores, from 1GB to 4GB of
memory. DomU with all cores is Windows Server 2008R2 Enterprise with
Terminal Services installed.

When I set cpu-weight to 192 (others have 256 - default), it starts to
lag. Applications became pretty slow and unstable.

Can someone help how CPU priority works with Xen? Is it stable already?
Where to start debug this issue.

Thanks
Jan