Fail to start the parallel pool in the Stand Alone Application compiled by mcc by MATLAB 2020b

Why the server cannot start the parallel pool?

Hi everyone,

My work flow is as below:

1. On the workstation: Ubuntu 22.04, I use MATLAB 2020b compiler to compile a stand alone executable file "parDebug".

This example file is to create a parallel pool with 2 processes (workers)

[ALLPROFILES, DEFAULTPROFILE] = parallel.clusterProfiles;

disp(['DEFAULTPROFILE = ',DEFAULTPROFILE]);

for idx = 1:numel(ALLPROFILES)

disp(['No. ',num2str(idx,'%d'),' profile = ',ALLPROFILES{idx}])

end

defaultCluster = parcluster(DEFAULTPROFILE);

p = parpool(defaultCluster,2);

disp(['We have ' num2str(p.NumWorkers,'%d'),' processes.']);

2. On the server: CentOS 7.06, I run the stand alone executable "parDebug" with MATLAB Compiler Runtime. The server have installed the MCR correctly.

The output is as following:

DEFAULTPROFILE = local
No. 1 profile = local
Starting parallel pool (parpool) using the 'local' profile ...

Error using parallel.Cluster/parpool (line 86)
Parallel pool failed to start with the following error.

Error in parDebug (line 11)

Caused by:
    Error using parallel.internal.pool.InteractiveClient>iThrowWithCause (line 676)
    Failed to initialize the interactive session.
        Error using parallel.internal.pool.InteractiveClient>iThrowIfBadParallelJobStatus (line 814)
        The interactive communicating job failed with no message.

parallel:cluster:PoolCreateFailed

The starting a parallel pool is always failing. The single thread code runs without problem. The server have 2 sockets of the multi-core CPU.

Why the server cannot start the parallel pool?

[Sam Marshalik]

Are you able to run MATLAB (not a compiled application) on that machine and run parpool? it would be good to understand if the issue is with how the compiled application is invoking the pool or if there is a more fundamental problem with starting a parallel pool on that machine.

[Xiaoqiu HE]

Hi Sam,

Thank you for the prompet answer!

In fact, on the server, I can start a pool of 4 processes. But I failed to start a pool with more than 4 processes.

I tried to validate the parallel profile, but I received the error: too many openning files.

Can you help me ?

Thanks very much!