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

tommylight
Topic Author
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Moderator

20 Jun 2020 22:32 - 21 Jun 2020 15:00 #172202 by tommylight

Results of latency test, list of computers tested for use with LinuxCNC was created by tommylight

Post the results of latency tests you have done on PC's and Laptops / Notebooks using the script downloaded from here:
forum.linuxcnc.org/18-computer/39370-scr...-of-computer-latency
Open the saved file with the ".hw" extension and paste the results here as code, or just attach that file here.
-This is meant as a database of what works, what is usable and what to avoid from the old and new computers, to have comparative results that can be used as a general guideline for choosing a computer for machine control.
-The script and the results are offered "as is" and therefore hold no liability, implicit or otherwise.

--Here is a link to some latency tests done before this script was in use, older pc's and laptops and some new ones:
forum.linuxcnc.org/18-computer/38838-har...ts-used-pc-s?start=0

Last edit: 21 Jun 2020 15:00 by tommylight. Reason: More info

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tommylight
Topic Author
Away
Moderator

20 Jun 2020 22:39 - 20 Jun 2020 22:46 #172205 by tommylight

Replied by tommylight on topic Results of latency test, list of computers tested for use with LinuxCNC

Here are the results of a Lenovo ThinkCentre M93, running for 2 minutes only, with no base thread:

LinuxCNC pc tests, version 20200619-c
********************************************************************************
General info:
LENOVO,  10A8S1BX0N
Bios version FBKT75AUS, dated 04/01/2014
Harddisk is non-rotational, ie. SSD
The amount of swap currently used is 8464
================================================================================
CPU related data:
model name	: Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz
cpu cores	: 4
stepping	: 3
cache size	: 6144 KB
================================================================================
RAM related data:
Maximum Capacity: 32 GB
Maximum Voltage: Unknown
Maximum Voltage: Unknown
Maximum Voltage: 1.5 V
Maximum Voltage: 1.5 V
Size: No Module Installed
Size: No Module Installed
Size: 4096 MB
Size: 2048 MB
================================================================================
GPU related data:
product: Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller
configuration: driver=i915 latency=0
================================================================================
Os related data:
PRETTY_NAME="Linux Mint 19.3"
Desktop: , Session: 
================================================================================
Kernel related data:
Kernel 5.4.0-0.bpo.4-rt-amd64
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
Cpu idle driver: intel_idle
================================================================================
Keyboard & Mouse related data:
Number of mice: 1
Mouse 0 : USB OPTICAL MOUSE 
Mice  attached to USB:
Keyboards attached to USB:
Dell Computer Corp. Multimedia Pro Keyboard
Dell Computer Corp. Multimedia Pro Keyboard Hub
LinuxCNC related data:
LinuxCNC version is: 2.9.0~pre0.2237.g829ce3e65
================================================================================
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' 

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

Latency testing loop started Sun Jun 21 00:39:38 CEST 2020, 
su cnc -c  "latency-histogram --nobase  --sbinsize 1000 --nox 2>&1 | tee  1592692755.lat &"
command for latency test is:
should end after Sun Jun 21 00:41:38 CEST 2020

Swap useage: prerun: 8464, running: 8464

================================================================================
last latency data is as follows:.
  125 secs  servo min: -74.000 uS max:  85.600 uS sdev:   7.700 uS
  126 secs  servo min: -74.000 uS max:  85.600 uS sdev:   7.700 uS

Last edit: 20 Jun 2020 22:46 by tommylight. Reason: results

The following user(s) said Thank You: seuchato

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seuchato
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22 Jun 2020 09:19 - 19 Oct 2020 11:17 #172308 by seuchato

Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC

OptiPlex 980, i5 CPU 650 @ 3.20GHz
Result with Buster

LinuxCNC pc tests, version 20200619-b
********************************************************************************
General info:
Dell Inc.,  OptiPlex 980                 
Bios version A04, dated 09/11/2010
Harddisk is non-rotational, ie. SSD
The amount of swap currently used is 1652
================================================================================
CPU related data:
model name	: Intel(R) Core(TM) i5 CPU         650  @ 3.20GHz
cpu cores	: 2
stepping	: 5
cache size	: 4096 KB
================================================================================
RAM related data:
Maximum Capacity: 16 GB
Size: 2048 MB
Size: 2048 MB
Size: No Module Installed
Size: No Module Installed
================================================================================
GPU related data:
product: Core Processor Integrated 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 "
Cpu idle driver: none
================================================================================
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~pre0.2237.g829ce3e65
================================================================================
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' 

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

Latency testing loop started Fr Jun 19 17:59:28 CEST 2020, 
should end after Fr Jun 19 19:59:28 CEST 2020
command for latency test is:
su xx -c  "latency-histogram --bbinsize 1000 --base 25000 --sbinsize 1000 --nox 2>&1 | tee  1592582351.lat &"
Cleaning up
Closing browser firefox
termiated latency ...
.terminated glxgears ...
.| .
 
 7206 secs  servo min: -19.300 uS max:  17.800 uS sdev:   0.700 uS
 7208 secs   base min: -19.900 uS max:  17.600 uS sdev:   0.300 uS

Result with mint:

LinuxCNC pc tests, version 20200622-pre
********************************************************************************
General info:
Dell Inc.,  OptiPlex 980                 
Bios version A04, dated 09/11/2010
Chipset: Intel Corporation 5 Series/3400 Series Chipset
Harddisk is non-rotational, ie. SSD
The amount of swap currently used is 0
================================================================================
CPU related data:
model name	: Intel(R) Core(TM) i5 CPU         650  @ 3.20GHz
cpu cores	: 2
stepping	: 5
cache size	: 4096 KB
================================================================================
RAM related data:
Maximum Capacity: 16 GB
Size: 2048 MB
Size: 2048 MB
Size: No Module Installed
Size: No Module Installed
================================================================================
GPU related data:
================================================================================
Os related data:
PRETTY_NAME="Linux Mint 19.3"
Desktop: MATE, Session: mate
================================================================================
Kernel related data:
Kernel 5.4.0-0.bpo.4-rt-amd64
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll isolcpus=1 "
Cpu idle driver: intel_idle
================================================================================
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:
Creative Labs 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' 

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

should end after Mo Jun 22 11:14:46 CEST 2020

Latency testing loop started Mo Jun 22 09:14:46 CEST 2020, 
command for latency test is:
su xx -c  "latency-histogram --bbinsize 1000 --base 25000 --sbinsize 1000 --nox 2>&1 | tee  1592810064.lat &"
Unexpected realtime delay on task 0 with period 25000

should end after Mo Jun 22 11:14:46 CEST 2020

Swap useage: prerun: 0, running: 0

================================================================================
last latency data is as follows:.
  164 secs   base min: -20.000 uS max:  22.000 uS sdev:   0.800 uS
  164 secs  servo min: -18.100 uS max:  16.900 uS sdev:   0.800 uS

PC seems suitable using Buster and kernel 4.19.0-9-rt-amd64. Not useable using mint and kernel 5.4.0-0.bpo.4-rt-amd64. Il try to use 4.19.0-9-rt-amd64 with mint and add the result here when done.

Greez
chris

Edit 19. Oct. 2020:

For BIOS settings, see this post here , at the bottom. Best BIOS version is A18.

Last edit: 19 Oct 2020 11:17 by seuchato. Reason: 19. Oct. 2020: Added reference to BIOS Settings and Version

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

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seuchato
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23 Jun 2020 10:41 - 23 Jun 2020 10:42 #172460 by seuchato

Replied by seuchato on topic Results of latency test, list of computers tested for use with LinuxCNC

Same machine on Mint with kernel 4.9.0-12-rt-amd64:

LinuxCNC pc tests, version 20200622-pre
********************************************************************************
General info:
Dell Inc.,  OptiPlex 980                 
Bios version A04, dated 09/11/2010
Chipset: Intel Corporation 5 Series/3400 Series 
Harddisk is non-rotational, ie. SSD
The amount of swap currently used is 0
================================================================================
CPU related data:
model name	: Intel(R) Core(TM) i5 CPU         650  @ 3.20GHz
cpu cores	: 2
stepping	: 5
cache size	: 4096 KB
================================================================================
RAM related data:
Maximum Capacity: 16 GB
Size: 2048 MB
Size: 2048 MB
Size: No Module Installed
Size: No Module Installed
================================================================================
GPU related data:
================================================================================
Os related data:
PRETTY_NAME="Linux Mint 19.3"
Desktop: MATE, Session: mate
================================================================================
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 "
Cpu idle driver: none
================================================================================
Keyboard & Mouse related data:
Number of mice: 2
Mouse 0 : Logitech USB Receiver
Mouse 1 : USB-compliant keyboard
Mice  attached to USB:
Logitech, Inc. Cordless Mouse Receiver
Keyboards attached to USB:
Creative Labs 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' 

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

Latency testing loop started Di Jun 23 09:16:06 CEST 2020, 

should end after Di Jun 23 11:16:06 CEST 2020
command for latency test is:
su xx -c  "latency-histogram --bbinsize 1000 --base 25000 --sbinsize 1000 --nox 2>&1 | tee  1592896550.lat &"

Swap useage: prerun: 0, running: 0

================================================================================
last latency data is as follows:.
 7205 secs   base min: -19.600 uS max:  18.700 uS sdev:   0.200 uS
 7205 secs  servo min: -26.700 uS max:  26.700 uS sdev:   0.700 uS

So, it is not mint, but the kernel.

Last edit: 23 Jun 2020 10:42 by seuchato.

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

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tommylight
Topic Author
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23 Jun 2020 16:13 #172484 by tommylight

Replied by tommylight on topic Results of latency test, list of computers tested for use with LinuxCNC

seuchato wrote:
So, it is not mint, but the kernel.

Mint will have a bit worse latency than Debian overall, but not by much. Kernel plays much more on latency

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chimeno
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23 Jun 2020 19:28 #172496 by chimeno

Replied by chimeno on topic Results of latency test, list of computers tested for use with LinuxCNC

Hello everyone, here are my results with my pc to experiment, very good program.

LinuxCNC pc tests, version 20200619-c
********************************************************************************
General info:
Gigabyte Technology Co., Ltd.,  P35-DS4
Bios version F14, dated 06/19/2009
Harddisk is non-rotational, ie. SSD
The amount of swap currently used is 0
================================================================================
CPU related data:
model name	: Intel(R) Core(TM)2 Quad CPU    Q6700  @ 2.66GHz
cpu cores	: 4
stepping	: 11
cache size	: 4096 KB
================================================================================
RAM related data:
Maximum Memory Module Size: 1024 MB
Maximum Total Memory Size: 4096 MB
Maximum Capacity: 4 GB
Maximum Memory Module Size: 1024 MB
Maximum Total Memory Size: 4096 MB
Installed Size: 2048 MB (Single-bank Connection)
Enabled Size: 2048 MB (Single-bank Connection)
Installed Size: 2048 MB (Single-bank Connection)
Enabled Size: 2048 MB (Single-bank Connection)
Installed Size: 2048 MB (Single-bank Connection)
Enabled Size: 2048 MB (Single-bank Connection)
Installed Size: Not Installed
Enabled Size: Not Installed
Size: 2048 MB
Size: 2048 MB
Size: 2048 MB
Size: No Module Installed
================================================================================
GPU related data:
product: Cypress PRO [Radeon HD 5850]
configuration: driver=radeon latency=0
================================================================================
Os related data:
PRETTY_NAME="Debian GNU/Linux 9 (stretch)"
Desktop: , Session: 
================================================================================
Kernel related data:
Kernel 4.9.0-11-rt-amd64
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
Cpu idle driver: none
================================================================================
Keyboard & Mouse related data:
Number of mice: 1
Mouse 0 : Logitech USB Receiver
Mice  attached to USB:
Keyboards attached to USB:
LinuxCNC related data:
LinuxCNC version is: 2.9.0~pre0
================================================================================
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' 

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

Latency testing loop started mar jun 23 19:35:35 CEST 2020, 
should end after mar jun 23 21:35:35 CEST 2020
su cnc -c  "latency-histogram --bbinsize 1000 --base 25000 --sbinsize 1000 --nox 2>&1 | tee  1592933718.lat &"
command for latency test is:

Unexpected realtime delay on task 0 with period 25000
should end after mar jun 23 21:35:35 CEST 2020

Swap useage: prerun: 0, running: 0

================================================================================
last latency data is as follows:.
    8 secs  servo min: -23.600 uS max:  23.300 uS sdev:   1.200 uS
   10 secs   base min: -24.600 uS max: 104.200 uS sdev:   1.500 uS

H/W path                 Device     Class          Description
==============================================================
                                    system         P35-DS4
/0                                  bus            P35-DS4
/0/0                                memory         128KiB BIOS
/0/4                                processor      Intel(R) Core(TM)2 Quad CPU    Q6700  @ 2.66GHz
/0/4/a                              memory         64KiB L1 cache
/0/4/b                              memory         4MiB L2 cache
/0/19                               memory         6GiB System Memory
/0/19/0                             memory         2GiB DIMM 800 MHz (1,2 ns)
/0/19/1                             memory         2GiB DIMM 800 MHz (1,2 ns)
/0/19/2                             memory         2GiB DIMM 800 MHz (1,2 ns)
/0/19/3                             memory         DIMM [empty]
/0/100                              bridge         82G33/G31/P35/P31 Express DRAM Controller
/0/100/1                            bridge         82G33/G31/P35/P31 Express PCI Express Root Port
/0/100/1/0                          display        Cypress PRO [Radeon HD 5850]
/0/100/1/0.1                        multimedia     Cypress HDMI Audio [Radeon HD 5830/5850/5870 / 6850/6870 Rebrand]
/0/100/1a                           bus            82801I (ICH9 Family) USB UHCI Controller #4
/0/100/1a/1              usb2       bus            UHCI Host Controller
/0/100/1a/1/2                       input          USB Receiver
/0/100/1a.1                         bus            82801I (ICH9 Family) USB UHCI Controller #5
/0/100/1a.1/1            usb4       bus            UHCI Host Controller
/0/100/1a.2                         bus            82801I (ICH9 Family) USB UHCI Controller #6
/0/100/1a.2/1            usb5       bus            UHCI Host Controller
/0/100/1a.7                         bus            82801I (ICH9 Family) USB2 EHCI Controller #2
/0/100/1a.7/1            usb1       bus            EHCI Host Controller
/0/100/1b                           multimedia     82801I (ICH9 Family) HD Audio Controller
/0/100/1c                           bridge         82801I (ICH9 Family) PCI Express Port 1
/0/100/1c.1                         bridge         82801I (ICH9 Family) PCI Express Port 2
/0/100/1c.1/0            eth1       network        82572EI Gigabit Ethernet Controller (Copper)
/0/100/1c.4                         bridge         82801I (ICH9 Family) PCI Express Port 5
/0/100/1c.4/0                       storage        JMB363 SATA/IDE Controller
/0/100/1c.4/0.1                     storage        JMB363 SATA/IDE Controller
/0/100/1c.5                         bridge         82801I (ICH9 Family) PCI Express Port 6
/0/100/1c.5/0            eth0       network        RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
/0/100/1d                           bus            82801I (ICH9 Family) USB UHCI Controller #1
/0/100/1d/1              usb6       bus            UHCI Host Controller
/0/100/1d/1/1                       communication  Bluetooth Dongle (HCI mode)
/0/100/1d.1                         bus            82801I (ICH9 Family) USB UHCI Controller #2
/0/100/1d.1/1            usb7       bus            UHCI Host Controller
/0/100/1d.2                         bus            82801I (ICH9 Family) USB UHCI Controller #3
/0/100/1d.2/1            usb8       bus            UHCI Host Controller
/0/100/1d.7                         bus            82801I (ICH9 Family) USB2 EHCI Controller #1
/0/100/1d.7/1            usb3       bus            EHCI Host Controller
/0/100/1d.7/1/2          scsi10     storage        USB2.0 Card Reader
/0/100/1d.7/1/2/0.0.0    /dev/sdc   disk           Reader
/0/100/1d.7/1/2/0.0.0/0  /dev/sdc   disk           
/0/100/1e                           bridge         82801 PCI Bridge
/0/100/1e/6                         bus            TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link)
/0/100/1f                           bridge         82801IR (ICH9R) LPC Interface Controller
/0/100/1f.2                         storage        SATA Controller [RAID mode]
/0/100/1f.3                         bus            82801I (ICH9 Family) SMBus Controller
/0/1                     scsi2      storage        
/0/1/0.0.0               /dev/sda   disk           250GB WDC WD2500AAJS-7
/0/1/0.0.0/1             /dev/sda1  volume         226GiB EXT4 volume
/0/1/0.0.0/2             /dev/sda2  volume         6141MiB Extended partition
/0/1/0.0.0/2/5           /dev/sda5  volume         6141MiB Linux swap volume
/0/2                     scsi5      storage        
/0/2/0.0.0               /dev/sdb   disk           1TB TOSHIBA MG03ACA1
/0/2/0.0.0/1             /dev/sdb1  volume         925GiB EXT4 volume
/0/2/0.0.0/2             /dev/sdb2  volume         6141MiB Extended partition
/0/2/0.0.0/2/5           /dev/sdb5  volume         6141MiB Linux swap volume

regards
Chimeno

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seuchato
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Platinum Member

24 Jun 2020 09:49 #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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seuchato
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Platinum Member

25 Jun 2020 03:21 - 18 Sep 2020 06:34 #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

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

... (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: 18 Sep 2020 06:34 by seuchato. Reason: typo

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seuchato
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Platinum Member

25 Jun 2020 08:59 #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

================================================================================
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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seuchato
Offline
Platinum Member

25 Jun 2020 14:54 #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

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

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