SMP support for Raspberry Pi 2

[Rohini Kulkarni]

 Hi,

I found this piece of code in confdefs.h

#if defined(RTEMS_SMP)

  /*
   *  If configured for SMP, then we need to know the maximum CPU cores.
   */
  #if !defined(CONFIGURE_SMP_APPLICATION)
    #if !defined(CONFIGURE_SMP_MAXIMUM_PROCESSORS)
      #define CONFIGURE_SMP_MAXIMUM_PROCESSORS 1
    #endif
  #else
    #if !defined(CONFIGURE_SMP_MAXIMUM_PROCESSORS)
      #error "CONFIGURE_SMP_MAXIMUM_PROCESSORS not specified for SMP
Application"
    #endif
  #endif
#endif

This piece of code gets the configured number of CPUs. I suppose this
number is not specified and will have to be specified by me somewhere in
the configurations. But I am unable to find out where.

Thanks!

On Sat, Jul 4, 2015 at 4:07 PM, Rohini Kulkarni <krohini1593 at gmail.com>
wrote:

>
>
> On Fri, Jul 3, 2015 at 10:43 PM, Joel Sherrill <joel.sherrill at oarcorp.com>
> wrote:
>
>>
>>
>> On July 3, 2015 11:53:07 AM CDT, Rohini Kulkarni <krohini1593 at gmail.com>
>> wrote:
>> >Any help that I can with this?
>> >
>> >On 1 Jul 2015 16:59, "Rohini Kulkarni" <krohini1593 at gmail.com> wrote:
>> >
>> >Hi all,
>> >
>> >I wish to know where the maximum number of processors for a variant are
>> >configured. I took a look at some configure scripts. I could see the
>> >processor count defined for xilinx-zynq in its configuration file as
>> >ZYNQ_CPUS=2.
>>
>   This looks to be BSP specific and could originate in configure.ac or a
> .h file.
> I found this under ~/libbsp/arm/xilinx-zynq/configure
> # Check whether --enable-smp was given.
> if test "$rtems_cv_HAS_SMP" = "yes"; then :
>   ZYNQ_CPUS="2"
> fi
>
>>
>> It is likely that each BSP has an underlying hardware limit.
>>
> Yes
>
>>
>> >
>> >rtems_configuration_get_maximum_processors() called in gets this
>> >configured number. But I don't know from where.
>>
>> This is set initially based on the confdefs.h parameter
>> CONFIGURE_SMP_MAXIMUM_PROCESSORS or something close to that (on phone).
>>
> Ya, I found this piece of code in confdefs.h
> #if defined(RTEMS_SMP)
>   /*
>    *  If configured for SMP, then we need to know the maximum CPU cores.
>    */
>   #if !defined(CONFIGURE_SMP_APPLICATION)
>     #if !defined(CONFIGURE_SMP_MAXIMUM_PROCESSORS)
>       #define CONFIGURE_SMP_MAXIMUM_PROCESSORS 1
>     #endif
>   #else
>     #if !defined(CONFIGURE_SMP_MAXIMUM_PROCESSORS)
>       #error "CONFIGURE_SMP_MAXIMUM_PROCESSORS not specified for SMP
> Application"
>     #endif
>   #endif
> #endif
>
> This piece of code gets the configured number of CPUs. I suppose this
> number is not specified and will have to be specified by me somewhere in
> the configurations. But I am unable to find out where.
>
>> Ultimately the maximum CPUs for an application is the lower of those
>> available or RTEMS is configured for.
>>
> Yes.
>
>>
>> >Also where is RTEMS_SMP defined for a bsp?
>>
>> A side-effect of building with --enable-smp.
>>
> Oh,alright.
>
>>
>>
>> >Thanks.
>> >
>> >
>> >--
>> >
>> >Rohini Kulkarni
>>
>> --joel
>>
>
>
>
> --
> Rohini Kulkarni
>



-- 
Rohini Kulkarni
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