Re: [Swarm-Modelling] SWARM on Clusters

[Marcus G. Daniels]

address@hidden wrote:

> When it comes down to
> executing, Swarm has to go through all the events and figure out which one
> runs next.
The cost comes at event insert time.  For most folks this is when the 
program plans what it wants to do (e.g. buildActions) or if the 
simulation is doing dynamic scheduling.  In normal situations, the 
figure-out-what-to-do-next cost is neglible.

> BTW clusters don't help much. They are designed to distribute the threads of a
> multi-threaded application. For all intents and purposes, Swarm is a single
> threaded application (when it comes to executing the model). So a cluster
> doesn't help at all.
>  
Even if Swarm was adapted to be multithreaded, a cluster wouldn't help 
due to communication costs.  Linux extensions like MOSIX work fine for 
migrating simple processes from machine to machine, but if the process 
that wants to be migrated has significant memory resources or I/O 
activity it won't move.  So, for example, agents that shared a landscape 
that was in RAM (especially swapping on RAM) on one computer would often 
get stuck on the computer having the memory resource, even though there 
were thousands of agents that would like to have a processor to themselves.