Re: [Machinekit] scheduling policy

[schoone...@gmail.com]

On 24/04/19 20:57, mngr wrote: Hi, I am trying to improve the latency on my Machinekit installation. As hardware I have an ASRock 90-MXB870-A0UAYZ. I have chosen this because I read about it in the linuxcnc forum. I am using Debian 9.8, with kernel 4.9 rt machinekit@debian:~$ uname -a Linux debian 4.9.0-8-rt-amd64 #1 SMP PREEMPT RT Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux The latency I have is 50 microsecond, and from what I have read it is a bit too high (it should be between 10 and 30 microsecond) so I started studying about latency in the rt kernel. A search of their site failed to find any ref to this MB, it is not in their latency-test list.  Do you have a link? All their testing will have been with rtai kernels (and then exaggerated very often). What is your aim, to do software stepgen and use a PCI parport board? You will need to look at isolcpus, acpi_irq_nobalance, noirqbalance etc.  Turn off hyper threading, virtualisation, suspend to RAM, most of power management. If that does not get you where you want to be, we have added support for libcgroup, partrt etc which has been tested on Intel processors to bring latency down dramatically. John Morris did a page in the docs here http://www.machinekit.io/docs/hal/threads-and-latency/ In theory this could be used with rt-preempt kernels for software stepgen. You need to read it carefully because the number of cores and how the L2 cache is organised are critical, don't know how AMD do it, haven't used one for yonks. regards -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.