AW: [Xen-users] CPU management

Antonino Catinello
Sat, 23 May 2009 08:56:06 -0000

Hi Christoph

Look into /etc/xen/xend-config.sxp and the setting (dom0-cpus 0) see the
explanation below from the config file.

# In SMP system, dom0 will use dom0-cpus # of CPUS
# If dom0-cpus = 0, dom0 will take all cpus available
(dom0-cpus 0)

Or look into this old mailinglist thread
http://lists.xensource.com/archives/html/xen-users/2006-02/msg00817.html I think
it explains a lot.

Hope that helps.

Antonino Catinello

-----Ursprüngliche Nachricht-----
Von: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] Im Auftrag von Christoph Kaminski
Gesendet: Samstag, 23. Mai 2009 10:33
An: xen-users
Betreff: [Xen-users] CPU management

Hi!


I have a system with i7 cpu. Quad core + hyperthreading == 4 cores and 8
cpu''s. I want to attach to a one domU exclusive 1 core == 2 cpus. With
this:

vcpus = 2
cpus = [ ''3'', ''7'' ]

I attach the 4th core and ht on this core to this domU. But if I do xm
vcpu-list, I see this:

Name                                ID  VCPU   CPU State   Time(s) CPU
Affinity
Domain-0                             0     0     4   r--   24725.7 any cpu
Domain-0                             0     1     1   -b-     414.5 any cpu
Domain-0                             0     2     1   -b-     410.6 any cpu
Domain-0                             0     3     2   -b-    1745.6 any cpu
Domain-0                             0     4     1   -b-     382.8 any cpu
Domain-0                             0     5     1   -b-     347.1 any cpu
Domain-0                             0     6     7   -b-     977.1 any cpu
Domain-0                             0     7     0   -b-    1843.5 any cpu
linux1                               2     0     5   -b-    1761.8 any cpu
linux2                               4     0     6   -b-    5045.3 any cpu
minixp-crypted                      16     0     0   -b-    1330.7 any cpu
minixp-test-crypted                 17     0     6   -b-    1677.7 any cpu
linux-important                      3     0     3   -b-    5897.5 3
linux-important                      3     1     7   -b-    3903.6 7

so the domU linux-important gets these cpu''s but all other get any cpu!
I can attach all other cpu''s to other domU''s with

vcpus = 1
cpus = ''0-2,4-6''

but how can I block these cpu''s to dom0?

It is generally a good idea? Or it is better to attach to this domU 2
vcpus and leave the cpu management in xen?

Greetz

PS: sorry for my english