Re: Fwd: Re: re[2]: Clusterwide pids

[<irbis@orcero.org>]

 Hello, Jordi!

> > Given the Alpha and the imminent arrival of the Itanium, I would prefer to
> > see a 64 bit CPID with the first 32 bits for the node and the last 32 bits
> > for the local pid.
>
> Fun, everytime the process migrate we'll have to change the PID (i assume
> this will be generic and cluster with processes migrating will use it)
>


 That is not the point. You select the CPID when the process start in this
way, but it does not depend on where is running, but where was born the
process.

 Rationale: Where the process is running is irrelevant on a SSI cluster.
We could have a mechanism, but it will not be commonly used. By the other
way, ensuring that a particular CPID is unique on the system when you create a
process is really complicated, and we must have a way to find a free CPID
without answering to the rest of the cluster, because we can have lots of
race conditions on the protocol that lead to two process with the same
CPID.

 Componing the CPID as <Origin node ID, local PID> assures that there will
be no two process with the same CPID, and there will be no weird race
conditions.

 Yours:

David


---------------------------
     irbis@orcero.org
http://www.orcero.org/irbis
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