Port Linux multiprocessor support

Port Linux multiprocessor support

[Giorgis Georgakoudis]

Hello all,

I would like to ask for some pointers regarding
porting Linux kernel multiprocessor support in
new platforms. More specifically, what are the
HW requirements that a platform must have to
enable Linux multiprocessing and some info
on kernel internals with respect to the booting
process, scheduling/migration etc.

I've been looking around for relevant documenta-
tion but found little to none.

Best regards,

Giorgis
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110819/12abd92d/attachment.html 

Port Linux multiprocessor support

[Greg KH]

On Fri, Aug 19, 2011 at 11:20:44AM +0300, Giorgis Georgakoudis wrote:
> Hello all,
> 
> I would like to ask for some pointers?regarding?
> porting Linux kernel multiprocessor?support in?
> new platforms.?More specifically, what are the
> HW requirements that a platform must have to
> enable Linux multiprocessing

It must have more than one processor and both must be able to see the
same system "image" at the same time.

> and some info
> on kernel internals with respect to the booting
> process, scheduling/migration etc.
> 
> I've been looking around for relevant?documenta-
> tion but found little to none.

Is the code not enough documentation for you for doing your porting
work?  What specifically do you find lacking?

greg k-h

Port Linux multiprocessor support

[Giorgis Georgakoudis]

On Fri, Aug 19, 2011 at 19:21, Greg KH <greg@kroah.com> wrote:

> On Fri, Aug 19, 2011 at 11:20:44AM +0300, Giorgis Georgakoudis wrote:
> > Hello all,
> >
> > I would like to ask for some pointers regarding
> > porting Linux kernel multiprocessor support in
> > new platforms. More specifically, what are the
> > HW requirements that a platform must have to
> > enable Linux multiprocessing
>
> It must have more than one processor and both must be able to see the
> same system "image" at the same time.


In fact, I'm trying to support multiprocessing in an experimental
architecture
of Microblazes on an FPGA. There isn't (HW) cache coherency and RAM is
accessed through per processor dedicated buses, thus shared access locking
must be realized either in a software manner or through a dedicated hardware
mutex.


>


> > and some info
> > on kernel internals with respect to the booting
> > process, scheduling/migration etc.
> >
> > I've been looking around for relevant documenta-
> > tion but found little to none.
>
> Is the code not enough documentation for you for doing your porting
> work?  What specifically do you find lacking?
>
> greg k-h
>

No doubt that the ultimate documentation is the code but still allow me
to consider that a higher level overview, abstracting code intricacies is
helpful.

Best regards,

Giorgis
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110819/9b4d2034/attachment-0001.html 

Port Linux multiprocessor support

[Greg KH]

On Fri, Aug 19, 2011 at 11:53:04PM +0300, Giorgis Georgakoudis wrote:
> 
> 
> On Fri, Aug 19, 2011 at 19:21, Greg KH <greg@kroah.com> wrote:
> 
>     On Fri, Aug 19, 2011 at 11:20:44AM +0300, Giorgis Georgakoudis wrote:
>     > Hello all,
>     >
>     > I would like to ask for some pointers?regarding?
>     > porting Linux kernel multiprocessor?support in?
>     > new platforms.?More specifically, what are the
>     > HW requirements that a platform must have to
>     > enable Linux multiprocessing
> 
>     It must have more than one processor and both must be able to see the
>     same system "image" at the same time.
> 
> 
> In fact, I'm trying to support multiprocessing in an experimental architecture
> of Microblazes on an FPGA. There isn't (HW) cache coherency and RAM is
> accessed through per processor dedicated buses, thus shared access locking?
> must be realized either in a software manner or through a dedicated hardware
> mutex.

Ah, that's going to take some work, good luck with that.