Re: SMP/cc Cluster description

[Jeff Dike]

[e-mail] said:
>  it seemed to me that you could easily  simulate what you want with
> lots of UML's talking to each other. I think you  would need to create
> some kind of device that uses a file or a shared memory  segment as
> the cluster's memory. 

Yeah, there is already support for mapping in a random file and using that
as UML memory, so that would be used for the cluster interconnect for any
cluster emulations you wanted to run with UML.

> Actually, I think that (shared memory) is  how
> Jeff had intended on implementing SMP in UML anyway.

No, at least not any shared memory that's not already there.  UML uses a 
host process for each UML process, and UML kernel data and text are
shared between all these host processes.  SMP just means having more than
one host process runnable at a time.  Each runnable process on the host
is a virtual processor.

> At this point I
> don't think UML supports SMP though I know of at least one person who
> was  attempting it.

It doesn't yet.  Someone is (or was), but I haven't heard a peep from him in
at least a month.  So this is starting to look like another little project
which got quickly going but just as quickly abandoned.

				Jeff