On 7/8/2015 9:51 AM, Hesham ALMatary wrote:
Hi Rohini,
On Wed, Jul 8, 2015 at 1:54 PM, Rohini Kulkarni <krohini1...@gmail.com> wrote:
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.
Every BSP that supports SMP should define the number of
cores/processors in its linkcmds file. For example have a look at
Realview linkcmds file here [1]
The pc386 treats the configured value as the maximum to be supported.
It does not hard code the number on the hardware but probes at run-time.
See libbsp/i386/shared/smp.
The key is that the BSP can set a hard limit or determine the available
set at run-time.
There are two factors:
+ number RTEMS is configured for
+ number present in hardware
- BSP can probe
- can be hard-coded
An RTEMS SMP application configured for 2 CPUs on a quad-core system
will simply ignore the other two.
[1]
https://github.com/RTEMS/rtems/blob/master/c/src/lib/libbsp/arm/realview-pbx-a9/startup/linkcmds.realview_pbx_a9_qemu_smp#L1
Thanks!
On Sat, Jul 4, 2015 at 4:07 PM, Rohini Kulkarni <krohini1...@gmail.com>
wrote:
On Fri, Jul 3, 2015 at 10:43 PM, Joel Sherrill <joel.sherr...@oarcorp.com>
wrote:
On July 3, 2015 11:53:07 AM CDT, Rohini Kulkarni <krohini1...@gmail.com>
wrote:
Any help that I can with this?
On 1 Jul 2015 16:59, "Rohini Kulkarni" <krohini1...@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
_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
--
Joel Sherrill, Ph.D. Director of Research & Development
joel.sherr...@oarcorp.com On-Line Applications Research
Ask me about RTEMS: a free RTOS Huntsville AL 35805
Support Available (256) 722-9985
_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
