Re: MPI/RT for Myrinet

It's my impression from reading that you will need a real-time kernel 
(that is, if you're using Linux/UNIX/Windows/Mac/etc). Without that basic, 
there is no support for realtime in GM - you must have the kernel 
interrupts to pass messages in realtime.

There is support for these kernels - you'll have to investigate your 
options.

Dan Strahs

On Thu, 28 Jul 2005, Patrick Geoffray wrote:

> Ashish Bijlani wrote:
> > On 7/28/05, Patrick Geoffray <[email protected]> wrote:
> > 
> >>Ashish Bijlani wrote:
> >>
> >>>Hi People,
> >>>
> >>>I've a setup of 8 nodes, each having M3F-PCIXD-2 interface. I want to
> >>>pass messages in Real-Time using MPI. Does this Myrinet interface
> >>>support Real-Time MPI(MPI/RT)?
> >>
> >>No. MPI/RT never really took off. I don't know anybody using it.
> >>
> > 
> > 
> > Can I use MPICH-GM in Real-Time to pass messages to other nodes? If
> > not, then what are the bottlenecks involved?
> 
> You can use MPICH-GM to pass messages, but you won't have hard real time 
> guarantees. First, you need a real time OS, and then you need to have 
> policies and admission control and scheduling in the NIC or in the lib 
> to guarantee the RT message deliveries. A lot of work.
> 
> >>>If not, then how can I pass messages in
> >>>Real-Time across nodes?
> 
> If your RT deadlines fits in the current best effort performance, you 
> have nothing to do, but you have no guarantees either.
> 
> Patrick
>