RPI4 Raspbian 64 bit & LinuxCNC

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15 Aug 2020 15:38 - 15 Aug 2020 15:50 #178299 by elovalvo
Install a fresh Raspbian 64 bit from this
Raspberry Pi OS (64 bit)

Following this link,
https://www.instructables.com/id/64bit-RT-Kernel-Compilation-for-Raspberry-Pi-4B-/
it's possible obtained a Raspbian 64bit RT-Preempt kernel. .

The kernel can be also download from:
rt64-kernel.tgz

Copy this file in /tmp and install:

cd /tmp
tar xzf rt64-kernel.tgz
cd boot
sudo cp -rd * /boot/
cd ../lib
sudo cp -dr * /lib/
cd ../overlays
sudo cp -dr * /boot/overlays
cd ../broadcom
sudo cp -dr bcm* /boot/

Edit /boot/config.txt file and add following line.
kernel=kernel8.img

then reboot.

The command.
uname -a
done this:
Linux raspberrypi 5.4.51-rt32-v8 #1 SMP PREEMPT_RT Fri Aug 14 16:57:40 CEST 2020 aarch64 GNU/Linux


Building LinuxCNC:

sudo apt update

sudo apt install devscripts
sudo apt install dh-python libudev-dev tcl8.6-dev tk8.6-dev asciidoc dblatex
sudo apt install libreadline-gplv2-dev docbook-xsl dvipng ghostscript graphviz
sudo apt install groff imagemagick inkscape python-lxml source-highlight
sudo apt install texlive-extra-utils texlive-font-utils texlive-fonts-recommended
sudo apt install texlive-lang-cyrillic texlive-lang-french texlive-lang-german
sudo apt install texlive-lang-polish texlive-lang-spanish texlive-latex-recommended
sudo apt install w3c-linkchecker xsltproc python-dev python-tk libxmu-dev
sudo apt install libglu1-mesa-dev libgtk2.0-dev intltool libboost-python-dev
sudo apt install libmodbus-dev libusb-1.0-0-dev desktop-file-utils yapps2
sudo apt install python-yapps bwidget libtk-img mesa-utils tclx8.4
sudo apt install tcl-tclreadline python-configobj python-gtkglext1
sudo apt install python-xlib gstreamer0.10-plugins-base netcat
sudo apt install python-pil python-glade2 python-pil.imagetk
sudo apt install python-gst-1.0 w3c-linkchecker libxmu-dev libtirpc-dev
sudo apt install gdebi gdebi-core

git clone github.com/LinuxCNC/linuxcnc.git emc
cd emc

debian/configure uspace
dpkg-checkbuilddeps

debuild -uc -us
cd ..

The .debs file can be also download from this link:
LinuxCNC_64bit.zip

Installing LinuxCNC:

cd ~/
wget ftp.it.debian.org/debian/pool/main/p/pyg...2_2.10.1-3_arm64.deb
sudo dpkg -i python-gtksourceview2_2.10.1-3_arm64.deb
sudo apt --fix-broken install

sudo gdebi linuxcnc-uspace_2.9.0~pre0_arm64.deb
sudo gdebi linuxcnc-uspace-dev_2.9.0~pre0_arm64.deb
sudo gdebi linuxcnc-doc-en_2.9.0~pre0_all.deb

This is latency test obtained from command:
latency-histogram --nobase --sbinsize 1000 --show

Attachments:
Last edit: 15 Aug 2020 15:50 by elovalvo.
The following user(s) said Thank You: phillc54, tommylight, BeagleBrainz

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16 Aug 2020 04:57 #178351 by phillc54
Great work, I followed your instructions and used your LinuxCNC package and it worked a treat.

I also built a Run In Place LinuxCNC 2.8 install withoput issues.

It has better latency than my old 32 bit version which also needed isolcpus=3 plus a few tweaks in cmdline.txt to get a reasonable latency. It is also much more responsive than the 32 bit version.

Thanks again.
The following user(s) said Thank You: elovalvo

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16 Aug 2020 15:33 #178411 by PCW
Replied by PCW on topic RPI4 Raspbian 64 bit & LinuxCNC
That's really good latency. If its reliable long term it would allow good step
generator/encoder performance using the RPI's GPIO.

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17 Aug 2020 00:16 #178437 by AgentWD40
@phillc54, is it running plasmac?

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17 Aug 2020 01:21 - 18 Aug 2020 03:13 #178446 by phillc54

AgentWD40 wrote: @phillc54, is it running plasmac?

I have only tried this 64bit version on a sim so far. I did run PlasmaC on the Pi4 with the 32bit version and if performed reasonably well. I run it headless using SSH. From what I have seen of the 64bit version it should perform better than before. Hopefully I will get some time this week to give it a try. The only issue is that you cannot use LinuxCNC 2.8 as it doesn't recognise the later PREEMPT_RT kernels.This is now fixed.
Last edit: 18 Aug 2020 03:13 by phillc54.

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17 Aug 2020 13:01 #178478 by bevins
Can we use this to connect to a 7i92/7i76?
And do a tool change with a remap of M6? possibly?

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17 Aug 2020 23:03 #178546 by phillc54
This is an overnight run with 10 glxgears:
Warning: Spoiler! [ Click to expand ]
Attachments:

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17 Aug 2020 23:43 #178555 by bevins
Right off the bat I got latency issues with the standard servo thread with a pncconf config. Tried dropping it and it got worse.
Thats with 7i92/7i76 connected and running.

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18 Aug 2020 03:16 #178564 by phillc54
I should have added that I had "processor.max_cstate=1" in /boot/cmdline.txt

This is a brief test with "processor.max_cstate=1 isolcpus=2,3" in /boot/cmdline.txt and 5 glxgears running.

Warning: Spoiler! [ Click to expand ]
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The following user(s) said Thank You: elovalvo, BeagleBrainz

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10 Sep 2020 00:38 #181530 by AgentWD40
So is that good? Can I run a 7i96 with this?

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