On 2/18/23 19:28, Rod Webster wrote:
Progress has been slow with the kernel stuff. I was able to build a non
PREEMPT_RT image for the Odroid N2++ and get it to boot yesterday.
Initially you need to boot from petitboot which sits on flash storage.
Step 2, adding the PREEMPT_RT patches failed after that. It seems the
armbian kernel 6.1 is a bit behind kernel.org so some of the patches from
November failed.
Kernel 6.2 is released today. My plan is to move to Armbian Edge which
already runs the 6.2 kernel before continuing. I need to get that sorted
bere trying xenomai
Gene, the Armbian build environment is run on an amd64 environment. I have
to say playing with kernels has shown you need a PC with 8-10 cores to get
it done in a reasonable time which is something my 10 year old i7 does not
have!
My rpi4 can build lcnc from git, buster master branch in around an hour
the last time I fired it off a couple months ago, but probably slower
today with all the new gfx in the docs. The docs take way more time than
lcnc.
I haven't actually built a new, running kernel in going on 3 years, but
I've built what I'm running in a bit over an hour. My build environment
is on a 240 gig SSD on the usb3 adaptor, so the only traffic for all
that does not touch the u-sd it boots from unless I install the debs it
makes for linuxcnc.
This is the kernel I built in Fed 2020:
Linux rpi4.coyote.den 4.19.71-rt24-v7l+ #1 SMP PREEMPT RT Thu Feb 6
07:09:18 EST 2020 armv7l GNU/Linux
latency-test shows about 12 u-secs for the 1khz servo-thread unless FF
is running, FF is a pig but you knew that. Even watching youtube the
lathe rarely stutters. but latency will hit 200 u-secs pretty easy then.
I have a standby and a small ups on the pi, so I determine uptimes, it
has never crashed,
pi@rpi4:~ $ uptime
01:38:13 up 124 days, 12:17, 3 users, load average: 0.46, 0.34, 0.26
I hope the next one I build is as stable.
Anyway, that 240g is about half full and I can clear out whatever it
take to make a new test mule out of it. Probably 100g of non-precious stuff.
Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au
On Sun, 19 Feb 2023 at 03:15, gene heskett <ghesk...@shentel.net> wrote:
On 2/18/23 11:31, Small Shop Concepts wrote:
That sounds awesome Rod! I am interested in your Xenomai 4 test results.
On Fri, Feb 10, 2023 at 3:53 AM Rod Webster <r...@vmn.com.au> wrote:
I was lucky enough to attend an Ethercat working group seminar today in
Brisbane, Australia where German based Martin Rostan, Executive
Director
from the EtherCAT Technology Group (ETG) was the main presenter.
It was all very interesting and the detailed low level description of
ethercat packets and alternatives based on TCP makes Ethercat streets in
front of other alternatives because of the sheer efficiency of the
protocol. This let me understand the issues causing the error finishing
read error being experienced with hm2eth connected devices (ie mesa
ethernet cards) in later kernels (5.10 and above).
I was also able to speak with Martin about the licensing issue
preventing us from including the Linuxcnc ethercat driver in our
distribution and have a greater understanding of the problem. Their
license requires users of an ethercat master (in this case the iGh
Etherlab
master we use) to become members of the ETG (which is free). Anybody
selling machines would need to adhere to this. So technically, we can't
put
that condition on to our terms because the existing GPL licence
from Linuxcnc propagates to the ethercat driver. He did go on to say
that
they would never take action against somebody promoting use of ethercat
masters.
So back to the error finishing read problem (that can't be solved by
wide
scale adoption of ethercat), I recently purchased an Odroid N2+ Arm
based
PC which arrived today. I was hoping the different platform may improve
network latency. I have been able to compile an Armbian bookworm image
which booted OK. A user on the Armbian forum is willing to help me
with
building a PREEMPT_RT image following this prerequisite first step. but
his
main interest is in Xenomai 4 and he is keen to help me subsequently
build
Xenomai for the N2+. Xenomai seems to have a significant advantage over
PREEMPT_RT re latency. Given we already support Xenomai 3, I am hoping
it
will be a fairly simple matter to support xenomai 4 and build a test for
network latency to look at differences between xenomai and preempt_rt.
So I am sure progress will be slow, but I am hopeful we will come up
with a
solution to error finishing read!
I hope some of you are interested in this ChatGPT free update!
Rod Webster
I too would be interested in Xenomai 4 as applied to armhf/arm64 stuff.
The kernel I first built as preempt-rt for the pi's has been decent but
is getting long in the tooth and although the installation of it on
armhf stuff is dead simple, its not really well fitting into the apt
update scheme, apt in fact ignores it. And while it can & does install
new kernels, it does not disable mine. So its safe to sudo apt update etc.
I am equipt to build kernels on my rpi4, or linuxcnc. And I keep
linuxcnc uptodate from github here. So I can supply another native build
environment for testing. Just ask.
VMN®
www.vmn.com.au
Ph: 1300 896 832
Mob: +61 435 765 611
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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
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