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Re: [Xen-users] xen only shows only ONE "cpu core"



I see the same behavior between Xen kernel showing cpu_cores=1
and non-xen kernel showing cpu_cores=4 on the dom0 of a very
similar machine.   Xen, and anything else, can still access
all the cores, it just reports them differently in /proc/cpuinfo
so that it makes it more difficult to detect a multi-core cpu
by parsing its output.

Steve Timm



On Fri, 18 Dec 2009, Israel Garcia wrote:

On 12/18/09, Steven Timm <timm@xxxxxxxx> wrote:

Is this on the dom0 or domU.
Hi, it's on a dom0.
processor is:
Intel(R) Xeon(R) CPU           E5410  @ 2.33GHz


If on the domU, what value of vcpus do you have
in the config file.

For what it's worth on my dom0 Xeon E5430 CPU running
xen kernel it shows 8 processor entries in /proc/cpuinfo
and shows each one of them with cpu cores : 1 too.
I have another server (not a xen kernel) which show 4 "cpu core". see below:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz
stepping        : 6
cpu MHz         : 2500.086
cache size      : 6144 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 4   <--- LOOK HERE
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 s
s ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good
pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca sse4_
1 lahf_lm
bogomips        : 5003.91
clflush size    : 64
cache_alignment : 64
address sizes   : 38 bits physical, 48 bits virtual
power management:

But this server runs a NON xen kernel. Both CPU's are quadcore.
That's why I'm  curious :)
Why with a normal kernel sees 4 cores and witn a xen kernel only one?
Same OS, almost same CPU (E5410-XEN_dom0 and E5420-NOT_XEN_SERVER)??

regards,
Israel.


Steve Timm


On Fri, 18 Dec 2009, Israel Garcia wrote:

Hi,
Do you know why xen kernel shows me only one "cpu cores" when there are 4?

see part of cat /proc/cpuinfo

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Xeon(R) CPU           E5410  @ 2.33GHz
stepping        : 10
cpu MHz         : 2333.430
cache size      : 6144 KB
physical id     : 0
siblings        : 1
core id         : 0
cpu cores       : 1    <---only ONE
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu de tsc msr pae cx8 apic sep mtrr cmov pat
clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_ts
c rep_good pni ssse3 cx16 sse4_1 lahf_lm
bogomips        : 4674.06
clflush size    : 64
cache_alignment : 64
address sizes   : 38 bits physical, 48 bits virtual
power management:

I'm running XEN on debian lenny:
grub-info:
title           Xen 3.2-1-amd64 / Debian GNU/Linux, kernel
2.6.26-1-xen-amd64
root            (hd0,0)
kernel          /xen-3.2-1-amd64.gz
module          /vmlinuz-2.6.26-1-xen-amd64 root=/dev/mapper/vg0-root
ro console=tty0
module          /initrd.img-2.6.26-1-xen-amd64

uname -r:
2.6.26-1-xen-amd64

regards,
Israel.

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--
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
timm@xxxxxxxx  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group
Leader.





--
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
timm@xxxxxxxx  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.

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http://lists.xensource.com/xen-users


 


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