Getting right tokens for preemption tasks and pre-empting a lot of delay tasks

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Andrea M39 asked Oct 18, '22 Jeanette F commented Nov 4, '22

Getting right tokens for preemption tasks and pre-empting a lot of delay tasks

Trying to find a good way to preempt tokens from a lot of delays (like 80) to change up resources with a shift change. I tried a couple of different ways to get the tokens, but none work great.

When I use the shared resource, like in the sample model attached, I get occasions where it grabs the tokens from the task it should be doing while preempted. I want it to re-acquire the resource before it goes back to the preempted delay task where it left off. I am also updating the number available in the resource based on a shift schedule. In my actual model, I have 11 different resources each with 10+ delays to represent concurrent operations tasks.

So, what is the best way to pre-empt tokens from many delay tasks (all with different names and times).

testPreempt.fsm

Thanks,

Andrea

Software Version:

FlexSim 22.2.2

preemting tokens preepmtion

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Jason Lightfoot ♦ commented · Oct 18, 2022 at 09:07 PM

Please retry the model upload - the link seems empty.

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Andrea M39 Jason Lightfoot ♦ commented · Oct 19, 2022 at 03:06 PM

tried again in the comments - meant to reply but seemed to have added a new comment

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Andrea M39 commented · Oct 19, 2022 at 03:05 PM

testPreempt.fsm

Updated some things and tried to re-attach the model. There is only a process flow in this model - no 3d Model stuff.

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testpreempt.fsm (41.8 KiB)

Jeanette F ♦♦ commented · Nov 04, 2022 at 05:02 AM

Hi @Andrea M39, was Jason Lightfoot's answer helpful? If so, please click the "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

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Answer 1 · 2022-10-20T18:44:02Z

Jason Lightfoot answered Oct 20, '22 Jason Lightfoot edited Oct 31, '22

Push and pull the preemptable tokens to/from a list and then refer to that list to get an array of tokens you can preempt.

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Andrea M39 commented · Oct 27, 2022 at 05:11 PM

I didn't think a list would help me here, but I will try it. I think I understand what you mean.

So if I push to the list and then release the token but keep on list, I can still pre-empt the delay, and come back to the delay using the same token. It is sort of in the core flow and on the list at the same time? I will try it today and see how it goes.

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Jason Lightfoot ♦ Andrea M39 commented · Oct 27, 2022 at 05:55 PM

preemptExample.fsm

Here's an example

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preemptexample.fsm (31.8 KiB)

Andrea M39 commented · Oct 31, 2022 at 02:18 PM

I don't see a way to do this that allows me to pre-empt the tokens, release the resources they have, then before they return to that same spot in the delay acquire a new resource.

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Jason Lightfoot ♦ Andrea M39 commented · Oct 31, 2022 at 03:33 PM

In that case don't use the prempting tokens, but release them from the delay and have them release the resources as you would when finishing normally. Use a flag on each token saying it has been preempted to route to a different part of the process and wait for reinsertion and reacquisition of the resources (as it would when normally routing through your process). Use a another label to store how much delay time was remaining or decrement the time in the delay from a 'remaining' delay time label.

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Getting right tokens for preemption tasks and pre-empting a lot of delay tasks

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