Port policy for STDSIMManager

In parallel computing, all Simcenter Amesim processes, which may be located on different machines, communicate through the network.

STDSIMBatch and STDSIMExplore are the master programs respectively for batch run and design exploration studies. STDSIMManager is the service started on all remote computing nodes to handle runs on a node. STDSIMManager manages multiple child processes (STDSIMDaemon) that perform the simulation run.  STDSIMManager and STDSIMDaemon use TCP ports to handle communication with the master process. Consequently you must enable incoming TCP communication on the cluster's network for STDSIM executables (for example: setting firewall exceptions for ports or particular executables on Windows).

Multiple STDSIMManagers can run simultaneously on the same node, but with different TCP ports. Multiple users can share a node as long as the STDSIMManagers use different TCP ports.  You are recommended to let Simcenter Amesim assign TCP ports on its own. Another possibility is to do port planning, and attribute a given base TCP port to each user.

In order to cope with a range of ports shared by different users, a strategy might be to allocate specific port numbers to different users (handling the ports as resources), each user running his simulation on the ports assigned to him.

• user 1 : 40100

• user 2 : 40200

• user 3 : 40300

Warning

STDSIMManager is actually deployed for every job on worker nodes. At the end of a job, the port is released by the STDSIMManager process, but the operating system sometimes delays port release for a few seconds. This means that a new STDSIMManager (from a new job started just afterwards on the same node) will be unable to bind the port as it is already in use, and the job will either fail or run with fewer resources than required. To avoid such situations, it is recommended to run with a port spread greater than 0.

The error tracker AMEHPCError retrieves this error.

Figure 9: Example of correct usage of ports for multiple STDSIMManagers on a single node