<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Hi Bjorn, thank you.</div><div><br></div><div>I am implementing a protocol based on MrsP, which involves the migration of tasks, but the protocol does not contemplate the suspension of tasks. I have not tried to reproduce this for the stock plugins. The plugin I'm using was implemented by a colleague, it also involves the migration of tasks.</div><div><br></div><div>I'll investigate what may be causing the tasks to be suspended. A starting point could be the migration of tasks?</div><div><br></div><div>Best regards,</div><div><br></div><div>Ricardo</div></div></div></div><br><div class="gmail_quote"><div dir="ltr">Em qui, 20 de dez de 2018 às 08:00, <<a href="mailto:litmus-dev-request@lists.litmus-rt.org">litmus-dev-request@lists.litmus-rt.org</a>> escreveu:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Send litmus-dev mailing list submissions to<br>
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1. Re: Zombie task after the experiment (Björn Brandenburg)<br>
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Message: 1<br>
Date: Wed, 19 Dec 2018 15:24:43 +0100<br>
From: Björn Brandenburg <<a href="mailto:bbb@mpi-sws.org" target="_blank">bbb@mpi-sws.org</a>><br>
To: <a href="mailto:litmus-dev@lists.litmus-rt.org" target="_blank">litmus-dev@lists.litmus-rt.org</a><br>
Subject: Re: [LITMUS^RT] Zombie task after the experiment<br>
Message-ID: <<a href="mailto:73215C20-3A09-4664-B0CD-7AA99ED2AFCE@mpi-sws.org" target="_blank">73215C20-3A09-4664-B0CD-7AA99ED2AFCE@mpi-sws.org</a>><br>
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<br>
Hi Ricardo,<br>
<br>
> On 12. Dec 2018, at 03:10, Ricardo Teixeira <<a href="mailto:ricardo.btxr@gmail.com" target="_blank">ricardo.btxr@gmail.com</a>> wrote:<br>
> <br>
> <br>
> I have been implementing a resource sharing protocol<br>
<br>
which protocol? Does it involve task migration? <br>
<br>
> for an existing multiprocessor scheduling algorithm in Litmus. <br>
<br>
Which plugin are you using? <br>
<br>
> Sometimes some tasks remain zombies after the time to stop the experiment. Debugging and investigating the logs, I noticed that these tasks pass through this code, inside kernel/sched/litmus.c<br>
> <br>
> /* check if the task became invalid while we dropped the lock */<br>
> if (next && (!is_realtime(next) || !tsk_rt(next)->present)) {<br>
> TRACE_TASK(next,<br>
> "BAD: next (no longer?) valid\n");<br>
> litmus->next_became_invalid(next);<br>
> litmus_reschedule_local();<br>
> next = NULL;<br>
> }<br>
> <br>
> I noticed that the value of the attribute called "present" is 0 at that point. <br>
<br>
This most likely means the plugin tried to schedule a task that is suspended. That should not be happening. Can you reliably reproduce this on a stock plugin? <br>
<br>
> This condition can make the task zombie? What can make this value equals to 0 and how can I avoid it?<br>
> The algorithm code does not set this value explicitly. <br>
<br>
It’s set to zero when a task suspends. See here:<br>
<br>
<a href="https://github.com/LITMUS-RT/litmus-rt/blob/4acc377593580e7d04ad8b42b258e8c2b39030ee/kernel/sched/litmus.c#L227" rel="noreferrer" target="_blank">https://github.com/LITMUS-RT/litmus-rt/blob/4acc377593580e7d04ad8b42b258e8c2b39030ee/kernel/sched/litmus.c#L227</a><br>
<br>
Regards,<br>
Björn<br>
<br>
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</blockquote></div></div>