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

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20 Jun 2020 22:32 - 21 Jun 2020 15:00 #172202 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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20 Jun 2020 22:39 - 20 Jun 2020 22:46 #172205 by tommylight
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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22 Jun 2020 09:19 - 19 Oct 2020 11:17 #172308 by seuchato
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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23 Jun 2020 10:41 - 23 Jun 2020 10:42 #172460 by seuchato
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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23 Jun 2020 16:13 #172484 by tommylight

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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23 Jun 2020 19:28 #172496 by chimeno
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
The following user(s) said Thank You: seuchato, tommylight

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24 Jun 2020 09:49 #172557 by seuchato
chimeno
kindly reply to this

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

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25 Jun 2020 03:21 - 18 Sep 2020 06:34 #172681 by seuchato
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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25 Jun 2020 08:59 #172695 by seuchato
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
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25 Jun 2020 14:54 #172735 by seuchato
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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