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Re: [Xen-users] xen cpu affinity, ie; pinning cpus

On Oct 22, 2009, at 12:13 PM, Tait Clarridge wrote:

On Thu, 2009-10-22 at 10:25 -0700, Brian Krusic wrote:

Yes, i read several article about having dom0 pinned to 1 cpu.

Funny thing is that I do this via xend-config-sxp and grub-conf but xm
vcpu-list still shows dom0 as "any" under affinity column.

When I run xm vcpu-pin Domain-0 0 0, xm vcpu-list then shows "0" under
the affinity column until I reboot.

Any ideas?

After setting (dom0-cpus 1) in /etc/xen/xend-config.sxp did you restart
the xend service?

If I remember correctly, it should be safe to do when domU's are

This should pin Domain-0 to cpu0.


[root@xxxxxx ]# xm vcpu-list
Name                              ID VCPUs   CPU State   Time(s) CPU
Domain-0                           0     0     0   r--  1648038.3 0
Domain-0                           0     1     -   --p       3.1 1
Domain-0                           0     2     -   --p       3.9 2
Domain-0                           0     3     -   --p       3.8 3
Domain-0                           0     4     -   --p       3.7 4
Domain-0                           0     5     -   --p       3.1 5
Domain-0                           0     6     -   --p       3.2 6
Domain-0                           0     7     -   --p       3.6 7
xendomainhere                      1     0     4   -b-  300000.1 any cpu

That shows that my vm host has 8 cores, but is only using one for
Domain-0.. the rest are in a paused state, so now what I can do is pin
them from the config files to use a core from cpus 1-7 or pin the domU
to a specific one as well.



Heres my grub.conf;

kernel /boot/xen.gz-3.4.1 dom0_max_vcpus=1 dom0_mem=1024M


(dom0-cpus 1)

Heres my xm vcpu-list after a reboot of the system;

Name            ID      VCPU    CPU     State   Time(s)         CPU Affinity
Domain-0        0       0               0               r--             216.6   
        any cpu

Heres my xm vcpu-list after xm vcpu-pin;

Name            ID      VCPU    CPU     State   Time(s)         CPU Affinity
Domain-0        0       0               0               r--             12585.6 

I tired to format this nice for you so please excuse if it come out like crap.

Notice the the CPU Affinity column.

Any ideas?

- Brian

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