[LITMUS^RT] litmus-dev Digest, Vol 22, Issue 1
Glenn Elliott
gelliott at cs.unc.edu
Tue Oct 1 15:32:44 CEST 2013
I'll take a look into this. Thank you for the information. One last thing you could try out for me:
1) Select the pfair scheduler.
2) As root, do "> rtspin 50 100 60" (rtspin is a part of liblitmus). This will launch a real time task with a period of 100ms and an execution time of ~50ms. The task will run for 60 seconds.
3) In another terminal, do 'top' and observe the CPU utilization of the real time task.
Is the observed utilization ~50% or is it 100%?
-Glenn
On Oct 1, 2013, at 9:18 AM, Mihai-Iulian Gheorghe <gheorghe at student.chalmers.se> wrote:
> Hi Glenn,
>
> I do not have any error codes. As I previously said, I have a dummy RT task, which just prints something at every period.
>
> More exactly, in the function "job()", I have a print statement. The problem is that, when I run this under PFAIR, the PERIOD I set is not taken into consideration, so basically it just runs an infinite loop, without any constraint:
>
> do {
> /* Wait until the next job is released. */
> sleep_next_period();
> /* Invoke job. */
> do_exit = job();
> } while (!do_exit);
>
>
> Maybe this bug is related to "sleep_next_period();", which should take care of the real time constraints, like the PERIOD.
>
> Thank you!
> Mihai
>
> -----Original Message-----
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> Sent: Tuesday, October 01, 2013 12:00 PM
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> Subject: litmus-dev Digest, Vol 22, Issue 1
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> 1. PFAIR policy (Mihai-Iulian Gheorghe)
> 2. Re: PFAIR policy (Glenn Elliott)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 30 Sep 2013 19:40:53 +0000
> From: Mihai-Iulian Gheorghe <gheorghe at student.chalmers.se>
> To: "litmus-dev at lists.litmus-rt.org" <litmus-dev at lists.litmus-rt.org>
> Subject: [LITMUS^RT] PFAIR policy
> Message-ID:
> <56a0e34aaf754cf5a222d506245e4a3a at BLUPR01MB129.prod.exchangelabs.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Hello,
>
> I am new to LITMUS and I am looking for some help. It seems that for some reason I am not able to run RT tasks under PFAIR. This policy is not taken into account.
>
> To be more precise, I have used the provided skeleton to write a real time task (just a dummy, that prints something periodically). The same RT task performs well under the other global scheduling policies and under the partitioned ones (with the note that for these policies, the RT task has been modified to run on a specific core, as required:
> param.cpu = CPU;
> be_migrate_to_partition(CPU);
> CALL( set_rt_task_param(gettid(), ¶m) ); ).
>
> Am I missing something? Please let me know if someone can help me. I am using the latest version of LITMUS - 2013.1. My system: Ubuntu 12.10, kernel version 3.10.5.
>
>
> Best regards,
> ---
> Mihai Gheorghe
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> ------------------------------
>
> Message: 2
> Date: Mon, 30 Sep 2013 15:48:30 -0400
> From: Glenn Elliott <gelliott at cs.unc.edu>
> To: litmus-dev at lists.litmus-rt.org
> Subject: Re: [LITMUS^RT] PFAIR policy
> Message-ID: <77E72CD2-B5DD-481C-A07D-5252665FE0E8 at cs.unc.edu>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Mihai,
>
> PFAIR doesn't get the same degree as testing as the other schedulers, so there may be a bug. Do you have any error messages/codes that you can share?
>
> Thanks,
> Glenn
>
>
> On Sep 30, 2013, at 3:40 PM, Mihai-Iulian Gheorghe <gheorghe at student.chalmers.se> wrote:
>
>> Hello,
>>
>> I am new to LITMUS and I am looking for some help. It seems that for some reason I am not able to run RT tasks under PFAIR. This policy is not taken into account.
>>
>> To be more precise, I have used the provided skeleton to write a real time task (just a dummy, that prints something periodically). The same RT task performs well under the other global scheduling policies and under the partitioned ones (with the note that for these policies, the RT task has been modified to run on a specific core, as required:
>> param.cpu = CPU;
>> be_migrate_to_partition(CPU);
>> CALL( set_rt_task_param(gettid(), ¶m) ); ).
>>
>> Am I missing something? Please let me know if someone can help me. I am using the latest version of LITMUS -2013.1. My system: Ubuntu 12.10, kernel version 3.10.5.
>>
>>
>> Best regards,
>> ---
>> Mihai Gheorghe
>> _______________________________________________
>> litmus-dev mailing list
>> litmus-dev at lists.litmus-rt.org
>> https://lists.litmus-rt.org/listinfo/litmus-dev
>
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