RPI4 Raspbian 64 bit & LinuxCNC

highlab.com/~seb/linuxcnc/rpi4-10us-latency.png

Seb on the IRC dev channel:
'it involves running each RT thread on its own dedicated CPU, and using busywait instead of sleep to start the next thread invocation
that's running on the arm64/aarch64 debian bookworm image from raspi.debian.net, not Raspberry Pi OS/raspbian
it's just a proof of concept at this point, i hope to clean it up and push it for review in the next week or two"

Hopefully transportable to actually available ARM boards vs Rpi.

Hello, elovalvo. Thank you for your work.

I used version 2. 8 from other topics before, and then I used your link Linux 5.15.65-rt49-v8 linuxcnc 2.9. But I found that raspberry pie is more stuttered than the previous version, flipping through your post, it seems that the delay effect of the 5.4.61-rt32-v8 version is better, but the previous link is no longer available. I hope you can provide the link to 5.4.61-rt32-v8 2.9. thank you very much.

Zuo99 wrote:

Hello, elovalvo. Thank you for your work.

I used version 2. 8 from other topics before, and then I used your link Linux 5.15.65-rt49-v8 linuxcnc 2.9. But I found that raspberry pie is more stuttered than the previous version, flipping through your post, it seems that the delay effect of the 5.4.61-rt32-v8 version is better, but the previous link is no longer available. I hope you can provide the link to 5.4.61-rt32-v8 2.9. thank you very much.

To make room in the google drive I deleted the versions that seemed outdated.

Now let's see if I saved that version you refer to somewhere, but I don't think so.

Or I try to reconstruct it as reported here
forum.linuxcnc.org/9-installing-linuxcnc...uxcnc?start=0#178299

For a possible fix for stuttering, see the last paragraph here:

forum.linuxcnc.org/38-general-linuxcnc-q...lved?start=10#256153

i've recently set up a raspberry pi 4b  with a Mesa 7i96S with stepper motors and am seeing multiple problems

after installing linucnc-2.9.0pre-bullseye_arm64rt.zip  as posted by elovalvo in:
forum.linuxcnc.org/9-installing-linuxcnc...cnc?start=150#253623

i am seeing multiple errors when running through my gcode:
it's not unusual to get "Unexpected realtime delay on task 0 with period 1000000"
the most common one happening during a run is "joint * following error"  (happens on any of the 3 joints)
and most catastrophic:  "hm2/hm2_7i96s.0: error finishing read"
as described in  Mesa hm2/hm2_7i96s.0: error finishing read
any suggestions would be greatly appreciated!

various diagnostics below, latency plot and hal file attached

linuxcnc@raspberrypi:~ $ uname -a
Linux raspberrypi 5.15.65-rt49-v8+ #1 SMP PREEMPT_RT Tue Sep 6 18:12:35 BST 2022 aarch64 GNU/Linux
===============
linuxcnc@raspberrypi:~ $ cat /proc/cpuinfo
processor       : 0
BogoMIPS        : 108.00
Features        : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd08
CPU revision    : 3

processor       : 1
BogoMIPS        : 108.00
Features        : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd08
CPU revision    : 3

processor       : 2
BogoMIPS        : 108.00
Features        : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd08
CPU revision    : 3

processor       : 3
BogoMIPS        : 108.00
Features        : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd08
CPU revision    : 3

Hardware        : BCM2835
Revision        : c03115
Serial          : 10000000ce7aa130
Model           : Raspberry Pi 4 Model B Rev 1.5

=================
Revision           : c03115
SoC                : BCM2711
RAM                : 4GB
Storage            : MicroSD
USB ports          : 4 (of which 2 USB3)
Ethernet ports     : 1 (1000Mbps max. speed)
Wi-fi              : True
Bluetooth          : True
Camera ports (CSI) : 1
Display ports (DSI): 1
===============
--- 10.10.10.10 ping statistics ---
1000 packets transmitted, 1000 received, 0% packet loss, time 1022926ms
rtt min/avg/max/mdev = 0.143/0.165/0.591/0.035 ms
=================
linuxcnc@raspberrypi:~ $ ethtool eth0
Settings for eth0:
        Supported ports: [ TP    MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Half 1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Half 1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: Symmetric
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Auto-negotiation: on
        master-slave cfg: preferred slave
        master-slave status: slave
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: external
        MDI-X: Unknown
netlink error: Operation not permitted
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes
==============
linuxcnc@raspberrypi:~ $ ethtool -S eth0 | column
NIC statistics:                      tx_oversize: 0
     rx_packets: 8628942             tx_defer: 0
     tx_packets: 11299821            tx_excess_defer: 0
     rx_bytes: 904320010             tx_single_col: 0
     tx_bytes: 1203609643            tx_multi_col: 0
     rx_errors: 0                    tx_late_col: 0
     tx_errors: 0                    tx_excess_col: 0
     rx_dropped: 0                   tx_frags: 0
     tx_dropped: 0                   tx_total_col: 0
     multicast: 0                    tx_jabber: 0
     rx_64_octets: 1249              tx_bytes: 1248832409
     rx_65_127_oct: 8627693          tx_good_pkts: 11299821
     rx_128_255_oct: 0               tx_unicast: 11298802
     rx_256_511_oct: 0               rx_runt_pkts: 0
     rx_512_1023_oct: 0              rx_runt_valid_fcs: 0
     rx_1024_1518_oct: 0             rx_runt_inval_fcs_align: 0
     rx_vlan_1519_1522_oct: 0        rx_runt_bytes: 0
     rx_1522_2047_oct: 0             rbuf_ovflow_cnt: 0
     rx_2048_4095_oct: 0             rbuf_err_cnt: 0
     rx_4096_9216_oct: 0             mdf_err_cnt: 0
     rx_pkts: 8628942                alloc_rx_buff_failed: 0
     rx_bytes: 938835778             rx_dma_failed: 0
     rx_multicast: 0                 tx_dma_failed: 0
     rx_broadcast: 0                 tx_realloc_tsb: 0
     rx_fcs: 0                       tx_realloc_tsb_failed: 0
     rx_control: 0                   txq0_packets: 1804878
     rx_pause: 0                     txq0_bytes: 209320936
     rx_unknown: 0                   rxq0_bytes: 0
     rx_align: 0                     rxq0_packets: 0
     rx_outrange: 0                  rxq0_errors: 0
     rx_code: 0                      rxq0_dropped: 0
     rx_carrier: 0                   txq1_packets: 1
     rx_oversize: 0                  txq1_bytes: 86
     rx_jabber: 0                    rxq1_bytes: 0
     rx_mtu_err: 0                   rxq1_packets: 0
     rx_good_pkts: 8628942           rxq1_errors: 0
     rx_unicast: 8628942             rxq1_dropped: 0
     rx_ppp: 0                       txq2_packets: 8025624
     rx_crc: 0                       txq2_bytes: 823705364
     tx_64_octets: 1649              rxq2_bytes: 0
     tx_65_127_oct: 8627688          rxq2_packets: 0
     tx_128_255_oct: 2669682         rxq2_errors: 0
     tx_256_511_oct: 802             rxq2_dropped: 0
     tx_512_1023_oct: 0              txq3_packets: 795
     tx_1024_1518_oct: 0             txq3_bytes: 262059
     tx_vlan_1519_1522_oct: 0        rxq3_bytes: 0
     tx_1522_2047_oct: 0             rxq3_packets: 0
     tx_2048_4095_oct: 0             rxq3_errors: 0
     tx_4096_9216_oct: 0             rxq3_dropped: 0
     tx_pkts: 11299821               txq16_packets: 1468523
     tx_multicast: 83                txq16_bytes: 170321198
     tx_broadcast: 936               rxq16_bytes: 904320010
     tx_pause: 0                     rxq16_packets: 8628942
     tx_control: 0                   rxq16_errors: 0
     tx_fcs_err: 0                   rxq16_dropped: 0
==============
linuxcnc@raspberrypi:~ $ ethtool -i eth0
driver: bcmgenet
version: 5.15.65-rt49-v8+
firmware-version: 
expansion-rom-version: 
bus-info: 
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no
================
linuxcnc@raspberrypi:~ $ ethtool -c eth0
Coalesce parameters for eth0:
Adaptive RX: off  TX: n/a
stats-block-usecs: n/a
sample-interval: n/a
pkt-rate-low: n/a
pkt-rate-high: n/a

rx-usecs: 57
rx-frames: 1
rx-usecs-irq: n/a
rx-frames-irq: n/a

tx-usecs: n/a
tx-frames: 10
tx-usecs-irq: n/a
tx-frames-irq: n/a

rx-usecs-low: n/a
rx-frame-low: n/a
tx-usecs-low: n/a
tx-frame-low: n/a

rx-usecs-high: n/a
rx-frame-high: n/a
tx-usecs-high: n/a
tx-frame-high: n/a

==============


 

As a first step, can you try with rx-usecs set to 0?

try isolcpus=2,3 as well

Can you also publish also the basicxyz.ini file?

try isolcpus=2,3 as well

when i run cat /sys/devices/system/cpu/isolated
it returns: 1-3

should it be changed to 2-3?
newbie question: where/how does one change that setting?

elovalvo, please see the attachments for the hal and ini files

thanks!