[PATCH] Add configuration option for single processor applications

[Richi Dubey]

Thanks for your quick review.

I think this patch is superfluous. In which scenario do you think it is
> necessary?

It is from this mail conversation:
https://lists.rtems.org/pipermail/devel/2020-September/061845.html
followed by
https://lists.rtems.org/pipermail/devel/2020-September/061846.html.

Strong APA uses the value of CONFIGURE_MAXIMUM_PROCESSORS in its declaration
<https://github.com/richidubey/rtems/blob/d3d1e4bc8e616738bd5892c59f82b174c399fc0b/cpukit/include/rtems/scheduler.h#L260>
at cpukit/include/rtems/scheduler.h. This addition would be necessary to
support future SMP schedulers that need to know the number of CPUs in the
system at the time of configuration.

>
>   /* Ensure that _CONFIGURE_MAXIMUM_PROCESSORS > 1 only in SMP
> configurations */
> #if defined(CONFIGURE_MAXIMUM_PROCESSORS) && defined(RTEMS_SMP)
>    #define _CONFIGURE_MAXIMUM_PROCESSORS CONFIGURE_MAXIMUM_PROCESSORS
> #else
>    #define _CONFIGURE_MAXIMUM_PROCESSORS 1
> #endif

I can see this in percpu.h. It's weird that make still gave an error!

On Tue, Mar 16, 2021 at 9:50 PM Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> On 16/03/2021 16:45, Richi Dubey wrote:
>
> > This change sets the value of number of processor as 1 for a single
> processor application.
> > Useful when trying to run a single processor application on a multi
> processor scheduler.
> I think this patch is superfluous. In which scenario do you think it is
> necessary?
>
> By default, exactly one processor is configured in all RTEMS build
> configurations.
>
> See:
>
> /* Ensure that _CONFIGURE_MAXIMUM_PROCESSORS > 1 only in SMP
> configurations */
> #if defined(CONFIGURE_MAXIMUM_PROCESSORS) && defined(RTEMS_SMP)
>    #define _CONFIGURE_MAXIMUM_PROCESSORS CONFIGURE_MAXIMUM_PROCESSORS
> #else
>    #define _CONFIGURE_MAXIMUM_PROCESSORS 1
> #endif
>
> --
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