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<p>Thanks for the reply. I think I get a little bit confused here. I tried to use the set cpu mask and set cpu affinity on Litmus, however it does not work. It seems that the Litmus ignored that.</p>
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<p>Also how can I use the<font color="#282828" size="3"> “Release Master”? Does that mean I have to the reconfiguration and then </font><font color="#282828">recompile</font><font color="#282828" size="3"> the kernel to do that?</font></p>
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<div>Zheng Luo<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> litmus-dev-bounces@lists.litmus-rt.org <litmus-dev-bounces@lists.litmus-rt.org> on behalf of Glenn Elliott <gelliott@cs.unc.edu><br>
<b>Sent:</b> Friday, December 13, 2013 9:15 PM<br>
<b>To:</b> litmus-dev@lists.litmus-rt.org<br>
<b>Subject:</b> Re: [LITMUS^RT] Question about how to specify dedicated cores to G-EDF and the relative deadline</font>
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<div>On Dec 13, 2013, at 11:00 PM, Luo, Zheng <<a href="mailto:luozheng@wustl.edu" title="mailto:luozheng@wustl.edu
Cmd+click or tap to follow link">luozheng@wustl.edu</a>> wrote:</div>
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<div style="margin-top:0px; margin-bottom:0px">Hi everyone,</div>
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<div style="margin-top:0px; margin-bottom:0px">I have a question about how to choose dedicated group of cores on Litmus running G-EDF. For example, if my machine have 4 cores, I want to reserve core 0 for the Operating system, and core 1-3 to the rt-thread
which can do the work. How can I do that? I tried the C-EDF, however used the L1,L2,L3 caches to do the division. I was wondering how can I do the division manually in the G-EDF?</div>
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<div style="margin-top:0px; margin-bottom:0px">Also, I have a question about the relative deadline, I think the normally the G-EDF should have the absolute deadline. Does the Litmus automatically convert <span style="font-size:12pt">relative deadline to the
absolute deadline when using the G-EDF?</span></div>
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<div style="margin-top:0px; margin-bottom:0px"><span style="font-size:12pt">Thanks, Looking forward to the reply. </span><span style="font-size:12pt"> </span></div>
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Zheng Luo</div>
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<div>Hi Zheng,</div>
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<div>I think you can accomplish what you want to do by using a “Release Master”. This is enabled by asserting the CONFIG_RELEASE_MASTER compile-time option under the “Scheduling” menu. This will reserve CPU0 (aka the “Release Master”) for handling release
interrupts for G-EDF running on the remaining CPUs. You can also run general code on the release master CPU, assuming you have properly configured CPU affinity masks for those processes/threads.</div>
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<div>All EDF schedulers, including G-EDF, always uses a job’s absolute deadline to prioritize scheduling. A relative deadline (a task attribute, not a job attribute) scheduler would be something like Deadline-Monotonic scheduling— tasks with smaller relative
deadlines have higher priority. Implementing your own Deadline-Monotonic scheduler is not hard. There are kludgey ways to do it in Litmus with just 5 to 10 minutes of coding.</div>
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<div>-Glenn</div>
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