https://forge.codesys.com/forge/talk/Runtime/thread/5f6058b284/2020-02-27T15:48:27.878000ZRecent posts to Linux Realtime Scheduler2020-02-27T15:48:27.878000Z2020-02-27T15:48:27.878000Zeschwellingerhttps://forge.codesys.com/u/eschwellinger/https://forge.codesys.coma0bc8de2d182b296e36b811b48baa947b255d504

<div class="markdown_content"><p>Hi,<br/> i have done no Tests with the CM3 so far,<br/> bubt even around 200 us is not so bad and for most Things good enough.</p> <blockquote> <p><strong>Zitat:</strong><br/> If I already have a License is there a possibility to purchase only a upgrade to multicore if deemed needed or do I need to buy a new license again</p> </blockquote> <p>No this is not possible - this is a different product with different price.</p> <p>BR<br/> Edwin</p></div>

2020-02-27T15:48:25.702000Z2020-02-27T15:48:25.702000Zhence.perssonhttps://forge.codesys.com/u/hence-persson/https://forge.codesys.com4c9f668fdca57feeb313153c289fa7cdb6a8af1a

<div class="markdown_content"><p>The problem may be that I am using a device Pigeon RB-300 which is based on a Rpi CM3.?<br/> The kernel is based on Raspbian Stretch Lite with kernel version 4.9.80 with Preempt RT patch.</p> <p>I am getting on a empty project in the Jitter colum a jitter value of 414us(-208/+206) in my task with prio 1.</p> <p>I tried to disable GPIO, SPI master etc no difference.</p> <p>So I guess with this hardware this is the best I can get.</p> <p>Another question..<br/> If I already have a License is there a possibility to purchase only a upgrade to multicore if deemed needed or do I need to buy a new license again?</p></div>

2020-02-27T15:48:24.788000Z2020-02-27T15:48:24.788000Zeschwellingerhttps://forge.codesys.com/u/eschwellinger/https://forge.codesys.come59a25a903b3d873683247eee3ed3cc836b145fd

<div class="markdown_content"><p>Hi,<br/> you just need to apply and rt_prempt kernel patch for your Linux kernel this is mandatory to have realtime and less jitter.<br/> That's it.<br/> You will see then on you Pi jitter &lt;150us and even better in the highest prio task.<br/> An additional option is the muclticore version of the PI. <br/> This will improve the jitter additional and a lot ( depending on how you distribute the application in the CODESYS project to your cores see the screen captures attached)<br/> BR<br/> Edwin</p> <p><img alt="IMG: Multicore2.png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=4560"/></p> <p><img alt="IMG: Multicore1.png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=4559"/></p></div>

2020-02-27T15:48:22.379000Z2020-02-27T15:48:22.379000Zhence.perssonhttps://forge.codesys.com/u/hence-persson/https://forge.codesys.comc79ebf96c2c0d87eb4890ce4f3a211c8b6d8d81a

<div class="markdown_content"><p>Hello.</p> <p>I have seen in the device description file that you have texts like these: &gt;<strong>Zitat:</strong><br/> realtime priority (SCHED FIFO 66)</p> <p>I was wondering when i have a realtime kernel does Codesys automatically create processes for the tasks that runs with SCHED_FIFO according to the device description?</p> <p>Because when looking with ps in the linux shell I can only see two codesys processes that are SCHED_OTHER. <br/> And I read on another forum a tip that I should schedule the two codesys processes as SCHED_RR to make Codesys run with lower Jitter... But that doesnt seem to change anything if I try It and that setting is lost when rebooting.</p> <p>Is there anything you can do to try and improve the jitter? I am not having any problems at the moment but I like to know these things so that when it becomes a problem I know what to do.</p></div>