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

[Steven Timm <timm@xxxxxxxx>]

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