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Results of latency test, list of computers tested for use with LinuxCNC

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6 years 4 months ago #172557 by seuchato
Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC
chimeno
kindly reply to this

... and thanks for the flowers anyway :-)
greez
chris

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6 years 4 months ago - 6 years 1 month ago #172681 by seuchato
Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC
Results for a hp 8300 sff, had to set interval for base thread to 50'000
Code:
LinuxCNC pc tests, version 20200624, started 25.06.2020 03:10:35 ******************************************************************************** General info: Hewlett-Packard, HP Compaq Elite 8300 SFF Bios version K01 v02.90, dated 07/16/2013 Chipset: Intel Corporation 7 Series/C216 Harddisk is non-rotational, ie. SSD The amount of swap currently used is 0 ================================================================================ CPU related data: model name : Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz cpu cores : 4 stepping : 9 cache size : 6144 KB ================================================================================ RAM related data: Maximum Capacity: 32 GB Size: No Module Installed Size: 4096 MB Size: No Module Installed Size: 4096 MB ================================================================================ GPU related data: product: Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller configuration: driver=i915 latency=0 ================================================================================ Os related data: PRETTY_NAME="Debian GNU/Linux 10 (buster)" Desktop: KDE, Session: ================================================================================ Kernel related data: Kernel 4.19.0-9-rt-amd64 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll isolcpus=1,2,3" Cpu idle driver: none ================================================================================ Kernel modules data: Check if pcspkr is loaded: No, good! Yes, may cause bigger latency. Check if snd modules are loaded: snd_hda_codec_hdmi 57344 1 snd_hda_codec_realtek 122880 1 snd_hda_codec_generic 86016 1 snd_hda_codec_realtek snd_hda_intel 49152 4 snd_hda_codec 151552 4 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec_realtek snd_hda_core 98304 5 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek snd_hwdep 20480 1 snd_hda_codec snd_pcm 114688 4 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_core snd_timer 36864 1 snd_pcm snd 102400 16 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek,snd_timer,snd_pcm soundcore 16384 1 snd Yes, may cause bigger latency. ================================================================================ Keyboard & Mouse related data: Number of mice: 1 Mouse 0 : Logitech USB Receiver Mice attached to USB: Logitech, Inc. Cordless Mouse Receiver Keyboards attached to USB: MosArt Semiconductor Corp. Defender Office Keyboard (K7310) S Zodiak KM-9010 LinuxCNC related data: LinuxCNC version is: 2.9.0~pre0.2245.g09397b8d3 ================================================================================ Preparing for latency test: Started glxgears No. 1 Started glxgears No. 2 Started glxgears No. 3 Started glxgears No. 4 Started glxgears No. 5 .......... Started firefox with 'https://vimeo.com/150574260' ================================================================================ Command for latency test is: su ck -c "latency-histogram --bbinsize 1000 --base 50000 --sbinsize 1000 --nox 2>&1 | tee 1593047417.lat &" Latency testing loop started Do Jun 25 03:10:49 CEST 2020, should end after Do Jun 25 05:10:49 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 7200 secs servo min: -39.000 uS max: 30.900 uS sdev: 3.400 uS 7201 secs base min: -31.500 uS max: 34.000 uS sdev: 0.600 uS

Same pc, but with a servothread only gives
Code:
... (hw summary see above) ================================================================================ Command for latency test is: su ck -c "latency-histogram --nobase --sbinsize 1000 --nox 2>&1 | tee 1593024764.lat &" Latency testing loop started Mi Jun 24 20:53:09 CEST 2020, should end after Mi Jun 24 22:53:09 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 7202 secs servo min: -63.400 uS max: 60.500 uS sdev: 3.800 uS 7203 secs servo min: -63.400 uS max: 60.500 uS sdev: 3.800 uS

Above results repeatedly achieved several times. Why is it that latency on serothread is appr. 1.5 - 2x the value of a run with a base thread?

greez
chris
Last edit: 6 years 1 month ago by seuchato. Reason: typo

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6 years 4 months ago #172695 by seuchato
Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC
Same hp 8300 sff, but with kernel 4.9.0-12-rt-amd64, basthread again at 25⁰000
Code:
================================================================================ Kernel related data: Kernel 4.9.0-12-rt-amd64 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll isolcpus=1,2,3" Cpu idle driver: none ================================================================================ ... ================================================================================ Command for latency test is: su ck -c "latency-histogram --bbinsize 1000 --base 25000 --sbinsize 1000 --nox 2>&1 | tee 1593058060.lat &" Latency testing loop started Do Jun 25 06:07:55 CEST 2020, should end after Do Jun 25 08:07:55 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 7205 secs base min: -18.000 uS max: 18.700 uS sdev: 0.500 uS 7205 secs servo min: -47.200 uS max: 44.900 uS sdev: 0.900 uS

lookee lookee: no rt delays!

greez
chris
The following user(s) said Thank You: tommylight, johnmc1

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6 years 4 months ago #172735 by seuchato
Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC
Still the same hp 8300 sff, same kernel, but this time w/o isolcpus. Got a realtime delay after 15 - 30 seconds, so the run below is for basthread interval 50'000 us
Code:
Hewlett-Packard, HP Compaq Elite 8300 SFF Bios version K01 v02.90, dated 07/16/2013 Chipset: Intel Corporation 7 Series/C216 Harddisk is non-rotational, ie. SSD The amount of swap currently used is 0 ================================================================================ CPU related data: model name : Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz cpu cores : 4 stepping : 9 cache size : 6144 KB ================================================================================ RAM related data: Maximum Capacity: 32 GB Size: No Module Installed Size: 4096 MB Size: No Module Installed Size: 4096 MB ================================================================================ GPU related data: product: Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller configuration: driver=i915 latency=0 ================================================================================ Os related data: PRETTY_NAME="Debian GNU/Linux 10 (buster)" Desktop: KDE, Session: ================================================================================ Kernel related data: Kernel 4.19.0-9-rt-amd64 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll" Cpu idle driver: none ================================================================================ ... Command for latency test is: su ck -c "latency-histogram --bbinsize 1000 --base 50000 --sbinsize 1000 --nox 2>&1 | tee 1593077144.lat &" Latency testing loop started Do Jun 25 11:26:10 CEST 2020, should end after Do Jun 25 13:26:10 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 7201 secs base min: -28.700 uS max: 26.900 uS sdev: 0.700 uS 7201 secs servo min: -37.800 uS max: 39.900 uS sdev: 1.100 uS

next, a run without base thread
Code:
================================================================================ Command for latency test is: su ck -c "latency-histogram --nobase --sbinsize 1000 --nox 2>&1 | tee 1593088904.lat &" Latency testing loop started Do Jun 25 14:42:08 CEST 2020, should end after Do Jun 25 16:42:08 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 7200 secs servo min: -72.800 uS max: 68.900 uS sdev: 3.100 uS 7201 secs servo min: -72.800 uS max: 68.900 uS sdev: 3.100 uS

Again: servo thread w/o base thread gets 1.5 to 2x the time as with base thread. I really wonder why?

Prel. conclusions:

  • isolcpus does not do too much on this machine
  • kernel matters
  • need to check preventing of loading of sound modules. (Unfortunately bios does not allow to disable audio)
  • looks like some useable pc, given it is gen 3 core cpu based, will probably be a good starting point for quite some time

    • greez
    chris
    The following user(s) said Thank You: tommylight, johnmc1

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    6 years 4 months ago #172788 by seuchato
    Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC
    Results of an old ASUS AT5MNI board: Got unexpected realtime delays even with base thread interval at 100'000! also the passive cooler on the board got very hot. So I guess, not useable at all.
    Code:
    LinuxCNC pc tests, version 20200624, started 25.06.2020 17:31:11 ******************************************************************************** General info: ASUSTeK Computer INC., System Product Name Bios version 0214, dated 12/01/2009 Chipset: Harddisk is non-rotational, ie. SSD The amount of swap currently used is 0 ================================================================================ CPU related data: model name : Intel(R) Atom(TM) CPU D510 @ 1.66GHz cpu cores : 2 stepping : 10 cache size : 512 KB ================================================================================ RAM related data: Maximum Capacity: 4 GB Size: 1024 MB Size: 1024 MB ================================================================================ GPU related data: product: Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller product: Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller configuration: driver=i915 latency=0 configuration: latency=0 ================================================================================ Os related data: PRETTY_NAME="Debian GNU/Linux 10 (buster)" Desktop: KDE, Session: ================================================================================ Kernel related data: Kernel 4.9.0-12-rt-amd64 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll" Cpu idle driver: none ================================================================================ Kernel modules data: Check if pcspkr is loaded: No, good! Yes, may cause bigger latency. Check if snd modules are loaded: No, good! Yes, may cause bigger latency. ================================================================================ Keyboard & Mouse related data: Number of mice: 2 Mouse 0 : USB-compliant keyboard Mouse 1 : Logitech USB Receiver Mice attached to USB: Logitech, Inc. Cordless Mouse Receiver Keyboards attached to USB: MosArt Semiconductor Corp. Defender Office Keyboard (K7310) S Zodiak KM-9010 LinuxCNC related data: LinuxCNC version is: 2.9.0~pre0.2258.gc90c1926d ================================================================================ Preparing for latency test: Started glxgears No. 1 Started glxgears No. 2 Started glxgears No. 3 Started glxgears No. 4 Started glxgears No. 5 .......... Started firefox with 'https://vimeo.com/150574260' ================================================================================ Command for latency test is: su ck -c "latency-histogram --bbinsize 1000 --base 100000 --sbinsize 1000 --nox 2>&1 | tee 1593099059.lat &" Latency testing loop started Do Jun 25 17:31:32 CEST 2020, should end after Do Jun 25 19:31:32 CEST 2020 Unexpected realtime delay on task 0 with period 100000 should end after Do Jun 25 19:31:32 CEST 2020 Swap useage: prerun: 0, running: 0 ================================================================================ last latency data is as follows:. 15 secs base min: -93.700 uS max: 121.000 uS sdev: 3.500 uS 15 secs servo min: -57.200 uS max: 59.600 uS sdev: 4.300 uS

    Greez
    chris

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    6 years 4 months ago #172792 by tommylight
    Replied by tommylight on topic Results of latency test, list of computers tested for use with LinuxCNC
    That might still be usable for running a Mesa board, be it PCI or PCI-E or Eth.
    LinuxCNC does not stress the PC as much as latency histogram does, so there will be less heat, but at the risk of having a bit worse latency than the histogram showed. Still usable, as it seems from the results.

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