Xen devel - Jun 2005 - Is there an equivalent to logical_proc_id ?

Hi,

  I am trying to port xenoprof to the latest version of xen-unstable
  and noticed the variable "logical_proc_id[]" that used to be defined
  in setup.c is gone. I spent sometime trying to find an equivalent
  variable/function without success.
 
  Does anyone know a simple way of determining the logical CPU id in
  a given physical CPU (i.e an id in the range [0,smp_num_siblings-1])?

  Thanks in advance for any help

  Renato

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* Santos, Jose Renato G <joserenato.santos@hp.com> [2005-06-20
14:10]:
> 
>   Hi,
> 
>   I am trying to port xenoprof to the latest version of xen-unstable
>   and noticed the variable "logical_proc_id[]" that used to be
defined
>   in setup.c is gone. I spent sometime trying to find an equivalent
>   variable/function without success.
>  
>   Does anyone know a simple way of determining the logical CPU id in
>   a given physical CPU (i.e an id in the range [0,smp_num_siblings-1])?
> 
>   Thanks in advance for any help
> 
>   Renato
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
I used the cpuid_apic id which I found in arch/i386/kernel/cpu/common.c
in the detech_ht() routine.

   unsigned int logical_proc_id;
   u32   eax, ebx, ecx, edx;

   cpuid(1, &eax, &ebx, &ecx, &edx);
   logical_proc_id = (ebx >> 24 & 0xff) & 1;


That worked for me when I was trying to get xenoprof to build/work
against unstable tree.


-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253
ryanh@us.ibm.com

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> -----Original Message-----
> From: Ryan Harper [mailto:ryanh@us.ibm.com] 
> Sent: Monday, June 20, 2005 12:28 PM
> To: Santos, Jose Renato G
> Cc: xen-devel@lists.xensource.com; Turner, Yoshio; Aravind 
> Menon; G John Janakiraman
> Subject: Re: [Xen-devel] Is there an equivalent to logical_proc_id[] ?
> 
> 
> * Santos, Jose Renato G <joserenato.santos@hp.com> [2005-06-20
14:10]:
> > 
> >   Hi,
> > 
> >   I am trying to port xenoprof to the latest version of xen-unstable
> >   and noticed the variable "logical_proc_id[]" that used to 
> be defined
> >   in setup.c is gone. I spent sometime trying to find an equivalent
> >   variable/function without success.
> >  
> >   Does anyone know a simple way of determining the logical CPU id in
> >   a given physical CPU (i.e an id in the range 
> > [0,smp_num_siblings-1])?
> > 
> >   Thanks in advance for any help
> > 
> >   Renato
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> 
> I used the cpuid_apic id which I found in 
> arch/i386/kernel/cpu/common.c in the detech_ht() routine.
> 
>    unsigned int logical_proc_id;
>    u32   eax, ebx, ecx, edx;
> 
>    cpuid(1, &eax, &ebx, &ecx, &edx);
>    logical_proc_id = (ebx >> 24 & 0xff) & 1;
> 
> 
> That worked for me when I was trying to get xenoprof to 
> build/work against unstable tree.
> 
> 
  
   Thanks Ryan

   I think you mean the code in xen/arch/x86/cpu/common.c.
   I think this would work when smp_num_siblings = 2. (i.e.
   Logical_proc_id is 0 or 1).

   Looking at the new code, it 
   looks like xen now support more than 2 logical CPUs per
   physical CPU. I am not sure if there is hardware available
   with more than 2 logical CPUs, but it seems we will need
   to support more than 2 HT per physical CPU in xenoprof, too.
   I was wondering if there is some macro that could be used
   to determine the logical CPU id in the more general case
   in which smp_num_siblings > 2?

   Anyway, thanks for the hint...

   Renato
> -- 
> Ryan Harper
> Software Engineer; Linux Technology Center
> IBM Corp., Austin, Tx
> (512) 838-9253   T/L: 678-9253
> ryanh@us.ibm.com
> 
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