Re: [SSI-users] Can OpenSSI Be Used for General-Purpose Computing?

[John H. <jo...@Ca...>]

Robert Wachinger wrote:
> On Mon, Sep 01, 2008 at 12:17:37PM +0200, John Hughes wrote:
>   
>> An OpenSSI cluster tries to look as much like one big multi-processor 
>> machine as possible.
>>     
>
> As far as I know, with one big difference:
>
> On a multiprocessor machine the OS' scheduler chooses automatically,
> on which processor a process will run.
> In OpenSSI the default is, that a process (with all of its threads)
> runs on the node, where it is started, unlesse you say explicitely
> otherwise (e.g. started in a "bash-ll", your application is made known
> to be able to migrate or so ...).
>
> Or is that not correct (any more)?
>   
Yup.  If /proc/pid/loadlevel is zero a process will not be moved from 
one node to another by the loadlevel logic.

If /proc/pid/pin is zero you can still migrate the process by hand (by 
writing a node number to /proc/pid/goto).

(As you say, the normal way of setting /proc/pid/loadlevel is to run 
/bin/bash-ll, or any other program mentioned in 
/proc/cluster/loadlevellist).