[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] IO performance depends on number of DomU's?



Hi,

is it always usefull if irqbalance is installed on Dom0 ?
Or maybe irqbalance is not usefull at all with Xen ?

Olivier

Fajar A. Nugraha a écrit :
On Tue, Apr 28, 2009 at 8:22 PM, Robert Dunkley <Robert@xxxxxxxxx> wrote:
Is it possible to dedicate one of the CPUs to Dom0 exclusively?

Yes.
Add this to the kernel boot line: dom0_max_vcpus=1
Edit /etc/xen/xend-config.sxp  -  set “(dom0-cpus 1)”
Reboot Dom0

Some additional info :
- you might also want this line on kernel boot line :dom0_vcpus_pin.
This would ensure that dom0's vcpu 0 (the active one if it only uses
one vcpu) is assigned on physical cpu 0 (or core 0 on multicore
system).
- those steps does not actually dedicate one CPU to dom0 exclusively.
What it does is it LIMITS dom0 to only use one CPU. To assign it
exclusively, you also need to tell domUs to NOT use that particular
CPU. Something like 'cpus="1-7"' (for 8-core system) on domU config
would tell it to NOT use core 0.However since current xen scheduler is
smart enough to assign cpu dynamically you might see the same result
with only the above config if your system load is low enough.
- to achive the same effect on your current session only without the
need to reboot:
xm vcpu-set 0 1
xm vcpu-pin 0 0 0

Regards,

Fajar

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.