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Ryusuke T avatar image
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Ryusuke T asked Ryusuke T commented

Behavior when using distributed CPUs

Hi,

I'm doing distributed CPU verification.

I noticed some strange behavior there.

First, confirm that you can connect to the external CPU, and then execute Optquest using the distributed CPU.

At this time, it can be confirmed that the distributed CPU processing is going well because the number of CPUs is exceeded.

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Next, I disconnected the network of the external PC and confirmed the disconnection from the properties.

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However, it seems that the number of CPUs used by OptQuest exceeds the number of CPUs it owns, and distributed CPUs continue to be enabled.

image4.png

what is happening?

FlexSim 23.0.8
optquestuse distributed cpus
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Joerg Vogel avatar image Joerg Vogel commented ·
@Ryusuke T , you are aware of multi-threading? A CPU computes two threads.
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Jordan Johnson avatar image Jordan Johnson ♦♦ Joerg Vogel commented ·
This question isn't related to hyper threading. If the user specifies that 2 CPUs are available, then only two child processes should be launched. The issue is that more child processes are being launched than were specified.
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Jason Lightfoot avatar image Jason Lightfoot ♦♦ Joerg Vogel commented ·

Hyper-Threading or Simultaneous Multi-Threading is where a single physical core presents two logical cores to the operating system for job allocation.

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1 Answer

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Jordan Johnson answered Ryusuke T commented

It is hard to say exactly what is happening. Based on your description, I would expect only 20 processes to run on the localhost, and none on the other computer. The optimizer should not show more than 20 active processes concurrently. It is not correct that there are 27.

I'm unable to replicate the issue on two computers on my network. If the "Use Distributed CPUs" box is checked, the number of concurrent processes is within what I specified in global preferences:

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If one of the connections is not available, then no processes are created for that connection, and the total number of processes is less:

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In order to further support you, I will need more information.

  • Do you get an exception in the system console, reporting that the disconnected host did not return valid ports?
  • Does the connected webserver report a request to create child processes, like this? Or does it not respond?1688761752706.png
  • Are you sure the "Use Distributed CPUs" box was not checked?

It may be helpful if you could record a video, or if we could arrange a web meeting.


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Ryusuke T avatar image Ryusuke T commented ·

@Jordan Johnson ,

In order to video record these problems, it is necessary to record the situation between two PCs, which is difficult.

Since this issue is not actually brought up by the customer, I will put it on hold for now.

We will contact you again when there is a report from the customer.

Thank you for your support.

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