Is concurrent execution not possible for a Simulink model with sample time less than 1ms ?

I have a simple simulink model same as the example Mathworks Data Parallelism. When I change the sample time of this model from 1 (original value in the sample model) to 0.0001 and try to build the model, simulink throws a block diagram error,

### Build procedure for model: 'data_parallel_model' aborted due to an error.
Error:  The periodic trigger Periodic of model data_parallel_model has a base rate smaller than 1 ms. The current base rate is 0.0001 seconds. Increase the base rate of the periodic trigger by increasing the rate in the model.

For easy reference, I have attached the snippet of the concurrent execution window,

The periodic Trigger has a period of 0.0001 and also the same for every Task under it.

Is this because the concurrent execution or the CPU cores have a Limitation for sample time less than 1ms or am I doing something wrong?

Answer 1

[shi chen]

Have you solved this problem?

[Bhavanithya Thiraviaraja]

The error did not arise when I increased the sample time to 1ms or more. I am not sure if this helps you.

Unfortunately, for my application, concurrent execution was not the optimal solution, so I had to drop it.

[shi chen]

I also changed the sample time to 1ms or more like you, and the model passed. But for my application, the sample time must be less than 100us. I have to manually write the code to assign tasks.

Answer 2

[Dimitri Lindt]

Hello, I have the same problem.

How can I automatically generate a code with a cycle time (periodic time/sample time) shorter than 1 ms?

Can one help?

Thanks in advance!

Answer 3

[Qing Liu]

I answered the same question here:

https://www.mathworks.com/matlabcentral/answers/446466-how-can-you-generate-a-c-code-with-embedded-coder-from-a-simulink-model-with-a-cycle-time-period-sa?s_tid=mlc_ans_email_ques

An tricky method : manually modify the tlc file( <MATLAB_ROOT>/rtw/c/tlc/mw/ertwinthread.tlc )

comment out lines 773-780 (as follow) from

773       %if ((period * 1000) < 1)
774         %if LibIsDeploymentDiagram()
775           %assign errormsg = "The periodic trigger %<LibGetTriggerName(ehIdx)> of model %<::CompiledModel.Name> has a base rate smaller than 1 ms. The current base rate is %<period> seconds. Increase the base rate of the periodic trigger by increasing the rate in the model."
776         %else
777           %assign errormsg = "%<::CompiledModel.Name> has a base rate smaller than 1 ms. The current base rate is %<period> seconds. Increase the base rate of the model."
778         %endif
779         %exit %<errormsg>
780       %endif

to this

773       /%%if ((period * 1000) < 1)
774         %if LibIsDeploymentDiagram()
775           %assign errormsg = "The periodic trigger %<LibGetTriggerName(ehIdx)> of model %<::CompiledModel.Name> has a base rate smaller than 1 ms. The current base rate is %<period> seconds. Increase the base rate of the periodic trigger by increasing the rate in the model."
776         %else
777           %assign errormsg = "%<::CompiledModel.Name> has a base rate smaller than 1 ms. The current base rate is %<period> seconds. Increase the base rate of the model."
778         %endif
779         %exit %<errormsg>
780       %endif%/

and the Code Generation process will skip the check of the time step greater than 1ms.

Hopes to help you!