real time SMP

real time SMP

Post by icur » Thu, 26 Jun 2003 01:06:39



Hi,

I wanted to know how the below mentd could be handled on a real-time SMP system.

 - binding a process/thread to a specific CPU ?
 - restricting a CPU's ability to execute some processes ? ie dedicated
 - restricting a CPU from running at all
 - forcing a cpu to run _only_ one process (and its children)
 - getting information about a CPU's state
 - creating/destroying sets of processors, to which processes may be bound

Thanks,

sk

 
 
 

real time SMP

Post by Werner Schweize » Fri, 27 Jun 2003 22:19:52


This is very dependant on the underlying OS.
As a starter loock at
http://www.qnx.com/resource/rs_pdf/SMP_at_a_Glance.pdf
Werner



Quote:> Hi,

> I wanted to know how the below mentd could be handled on a real-time SMP
system.

>  - binding a process/thread to a specific CPU ?
>  - restricting a CPU's ability to execute some processes ? ie dedicated
>  - restricting a CPU from running at all
>  - forcing a cpu to run _only_ one process (and its children)
>  - getting information about a CPU's state
>  - creating/destroying sets of processors, to which processes may be bound

> Thanks,

> sk


 
 
 

real time SMP

Post by Werner Schweize » Fri, 27 Jun 2003 22:25:10


http://www.qnx.com/resource/rs_pdf/rs_smp_howto_qnx.pdf



> This is very dependant on the underlying OS.
> As a starter loock at
> http://www.qnx.com/resource/rs_pdf/SMP_at_a_Glance.pdf
> Werner



> > Hi,

> > I wanted to know how the below mentd could be handled on a real-time SMP
> system.

> >  - binding a process/thread to a specific CPU ?
> >  - restricting a CPU's ability to execute some processes ? ie dedicated
> >  - restricting a CPU from running at all
> >  - forcing a cpu to run _only_ one process (and its children)
> >  - getting information about a CPU's state
> >  - creating/destroying sets of processors, to which processes may be
bound

> > Thanks,

> > sk

 
 
 

real time SMP

Post by icur » Sat, 28 Jun 2003 02:46:07


Thanks.

I went through the docs pointed out by the url provided. It looks like
we can set the processor affinity but still there is no guarantee that
other processes wouldn't run on the same CPU and hog its time. In real
time environment, latency is a big concern. The qnx doesn't mention
anything about interrupts. Ideally, I wouldn't like interrupts to
preempt my real-time task. I sure can dedicate a separate processor to
handle interrupts and other OS tasks.

Someone on the other forum pointed me towards 'shielded processor':
(url)

http://www.linuxdevices.com/articles/AT8610061752.html

It looks like it can isolate real-time tasks, interrupts and other OS
tasks on different CPUs. Not Open source though.


> http://www.qnx.com/resource/rs_pdf/rs_smp_howto_qnx.pdf



> > This is very dependant on the underlying OS.
> > As a starter loock at
> > http://www.qnx.com/resource/rs_pdf/SMP_at_a_Glance.pdf
> > Werner



> > > Hi,

> > > I wanted to know how the below mentd could be handled on a real-time SMP
>  system.

> > >  - binding a process/thread to a specific CPU ?
> > >  - restricting a CPU's ability to execute some processes ? ie dedicated
> > >  - restricting a CPU from running at all
> > >  - forcing a cpu to run _only_ one process (and its children)
> > >  - getting information about a CPU's state
> > >  - creating/destroying sets of processors, to which processes may be
>  bound

> > > Thanks,

> > > sk

 
 
 

real time SMP

Post by Hans Adam » Wed, 02 Jul 2003 05:36:13



> Hi,

Is it homework yet to be done, or a serious topic?

Quote:

> I wanted to know how the below mentd could be handled on a real-time SMP system.

_realtime_ and SMP? Are you going to build your own one, or use an
existing one?

How about Chorus, see http://docs.sun.com?

Quote:>  - binding a process/thread to a specific CPU ?

thread bind.

Quote:>  - restricting a CPU's ability to execute some processes ? ie dedicated
>  - restricting a CPU from running at all
>  - forcing a cpu to run _only_ one process (and its children)

Is done per default.

Quote:>  - getting information about a CPU's state

svActorMon

Quote:>  - creating/destroying sets of processors, to which processes may be bound

???? Scheduler should decide on its own, when resources are getting
scarse (spelling ??) ??

Quote:> Thanks,

> sk

best HAns Adams
 
 
 

real time SMP

Post by Eric Dujardi » Wed, 02 Jul 2003 18:23:04




>> Hi,

> Is it homework yet to be done, or a serious topic?

>> I wanted to know how the below mentd could be handled on a real-time
>> SMP system.

> _realtime_ and SMP? Are you going to build your own one, or use an
> existing one?

> How about Chorus, see http://docs.sun.com?

Hello Hans,

Chorus is not sold by Sun any more. The Chorus microkernel and ChorusOS 5.0 have
been put open-source by Sun, and are now part of the Jaluna offering. Indeed, the
Jaluna-1 RTOS is the follow-up to ChorusOS 5.0. Jaluna also supports the ChorusOS
releases which have been done by Sun, and earlier by Chorus Systems. See www.jaluna.com
for more information.

Anyway, the SMP feature of the microkernel have not been enabled in a release
for a long time. One could still find references to it in the main API, as well
as some #ifdef's in the source, but it is definitely not usable. This could
be enabled again as many original Chorus implementors are with Jaluna today, but
it would naturally be a significant task.

Best,

Eric

Eric
----------------------------------------
firstname dot lastname at jaluna dot com
www.jaluna.com