Re[2]: [Qemu-devel] Re: request : qemu-smp as target

[Igor Shmukler]

Hi,

I mostly agree with everything said, but I'd like to add some thoughts tp the 
pot.

I think it's important to understand that that a product that coverts clusters 
to 
virtual MP could be designed with different requirements in mind.

We are working on a research project that represents cluster as a NUMA machine. 
This 
is enough for a NUMA aware OS and performace is not bad.

If we were to make a regular SMP, it would probably not work as well.

I am not a Mosix guy, but I would think that installing QEMU on OM will solve 
nothing. It will only shift problems to be addressed at a different layer. 
Maybe I 
am wrong

Sincerely,

Igor.

> In the applications, probably very independent.  In the kernel, highly 
> dependent: different CPUs may access shared data structures *and* protect 
> them with spinlocks.  As Paul said in a separate mail, spinlocks are going to 
> be way more expensive in this sort of distributed environment.
> 
> All that being said, a company called "Virtual Iron" has got a 
> fully-virtualising solution that presents an SMP to the guest OS but actually 
> distributes computation across a cluster.  I have yet to see the product 
> itself - no idea when it'll be released.  It also sounds *really* difficult 
> to make go fast but at least suggests this sort of thing can perform 
> reasonably for some workloads.
> 
> Cheers,
> Mark