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

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6 years 2 days ago #187848 by my1987toyota
Thank you Clive S . I am sure everyone is thanking you for telling me that.
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6 years 2 days ago #187851 by my1987toyota
this is of the 2 hour test
Code:
LinuxCNC pc tests, version 20200930, started 30.10.2020 17:59:09 ******************************************************************************** General info: Dell Inc., OptiPlex 7010 Bios version A29, dated 06/28/2018 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 ================================================================================ Parallel port related data: number of parallel ports is 0 ================================================================================ Os and desktop related data: PRETTY_NAME="Debian GNU/Linux 10 (buster)" Should the info below not match with your machine, kindly post the output of pstree here, including a brief desciption of your desktop environment, window manager and display manager. Tia https://forum.linuxcnc.org/18-computer/39370-script-for-automated-testing-of-computer-latency Desktop environment : xfce4 Windowmanager : Xfwm4 Displaymanager : lightdm ================================================================================ Kernel related data: Kernel 4.19.0-11-rt-amd64 GRUB_CMDLINE_LINUX_DEFAULT="quiet" Cpu idle driver: intel_idle ================================================================================ Kernel modules data: Check if pcspkr is loaded: Yes, may cause bigger latency. can be eliminated using: sudo echo "install pcspkr /bin/true" >/etc/modprobe.d/pcspkr.conf Check if snd modules are loaded: Yes, may cause bigger latency. can probably be disabled in bios, alternatively, you can run "./block-snd-modules" which has just now been created for your convenience. ================================================================================ Keyboard & Mouse related data: Number of mice: 1 Mouse 0 : PixArt USB Optical Mouse Mice attached to USB: Keyboards attached to USB: Dell Computer Corp. Keyboard ================================================================================ LinuxCNC related data: LinuxCNC version is: 2.8.0 ================================================================================ Preparing for latency test: Started glxgears No. 1, 2, 3, 4, 5 .......... Started firefox with 'https://vimeo.com/150574260', WID 50331651 ================================================================================ Command for latency test is: su cnc -c "latency-histogram --nobase --base 25000 --sbinsize 1000 --nox 2>&1 | tee -a 1604095133.lat &" Latency testing loop started Fri 30 Oct 2020 05:59:23 PM EDT, should end after Fri 30 Oct 2020 07:59:23 PM EDT ================================================================================ Swap useage: prerun: 0, running: 0 ================================================================================ CPU core temperatures: Core 0: Tmin: 50.0°C, Tmax: 68.0°C, (high = +85.0°C, crit = +105.0°C) Core 1: Tmin: 56.0°C, Tmax: 74.0°C, (high = +85.0°C, crit = +105.0°C) Core 2: Tmin: 54.0°C, Tmax: 72.0°C, (high = +85.0°C, crit = +105.0°C) Core 3: Tmin: 52.0°C, Tmax: 71.0°C, (high = +85.0°C, crit = +105.0°C) ================================================================================ last latency data is as follows:. 7201 secs servo min: -82.900 uS max: 69.600 uS sdev: 3.200 uS 7202 secs servo min: -82.900 uS max: 69.600 uS sdev: 3.200 uS
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6 years 2 days ago - 6 years 2 days ago #187853 by BeagleBrainz
Just out of interest why is the --nobase & --base options being used ?

Can anyone explain the binsize parameter.
It does seem to affect latency, but which size 0.1us or 1.0us gives a result that matches real world use ?

For instance, althouhg short test there was a difference seen:

Binsize as per script:


Binsize as a default when running just with the base switch:
Last edit: 6 years 2 days ago by BeagleBrainz.

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6 years 2 days ago - 6 years 2 days ago #187860 by seuchato
@my1987toyota

Do you need pcspkr and sound modules? If not, disable them in bios or block the kernel modules to be loaded. Depending on what PC, I usually get much better latency, if these modules are not loaded.
Last edit: 6 years 2 days ago by seuchato.
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6 years 2 days ago #187861 by seuchato
@BeagleBrainz

"latency-histogram --nobase --base 25000 --sbinsize 1000 --nox"

This is a bug in the script. I'll change that. Thanks for getting this pointed out.

Greez

chris

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6 years 2 days ago #187862 by seuchato

BeagleBrainz wrote: ...

Can anyone explain the binsize parameter.
It does seem to affect latency, but which size 0.1us or 1.0us gives a result that matches real world use ?

For instance, althouhg short test there was a difference seen:

Binsize as per script:



Binsize as a default when running just with the base switch:


The two tests do show very similar data (given the test ran only for 7/8 secs), but the x-scale of the plot differ by a factor of 10. And that's exactly controlled by binsize: resolution of the diagram in x-axis.

hth
chris
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