Linuxcnc high latency. I am running linuxcnc 2.

Linuxcnc high latency I think it may need to say rt-preempt or something. ) I have noticed that the EliteDesk has significantly higher latency even restricted to a single core I understand, in the case here I installed linuxcnc / debian in HD and then hung up the drive CD / DVD and the latency was between 15000 and 17000, as I will not need to use the drive dvd / cd there can let him off. 90, dated 05/21/2018 Chipset: Harddisk is non-rotational The Latency Problem ***** This subject must be the single most vexed and most frequently discussed subject in relation to running Linuxcnc, on LinuxCNC requires real time (low predictable latency) and ability to meet the thread invocation rate for the servo and possibly base threads. 10), but when I start Linuxcnc I get these two errors. I am getting consistent results with latency-test in the <9000 for base and <10000 for servo over an 8 hour run (2 of them) I ran latency-histogram and that shows rare but consistent spikes of >30-50 uSec. LinuxCNC pc tests, version 20200930, started 06. RTAI Latency test. 0°C) As alluded to in the FAQ on latency problems, the base Ubuntu system kernel version and the Linuxcnc kernel version based upon it, can have a profound effect, not only upon latency, but whether you can even install from Live CD and if you can, whether it will run. I am running linuxcnc 2. here you asked for:. Each process is given (or asks for) a priority number, and the real-time kernel will always give processing time to the process with the highest priority number, even if that process uses up all of the available processing time. I do get latency errors from linuxcnc. For details, see WhatLatencyTestDoes. Thanks for the answer. Some tuning parameters to look into: So I'm new to linuxcnc, and just a hobby machinist. Then it parses the remainder of the command line for user The latency test is important when configuring a LinuxCNC system. In addition LinuxCNC needs to be run on an operating system that uses a specially modified kernel, see I tried to update EMC2 to 10. The latency numbers my old computer gave me weren't that good and so i recently got obsessed by the idea to get sub 4k latency. In a default LinuxCNC installation, latency-test is found in the <linuxcnc>/scripts directory. With no special configuration their latency figures are ok, but not amazing, even with relatively new, higher spec machines, so I was a little disappointed. -Does not work on Debian Wheezy Linux. I got max jitter on servo thread 1553904. A higher servo thread rate may also be required if a torque Hi All, I'm having trouble reducing the latency on my computer. I spent hours reading posts here and comparing the machines listed on the latency-test wiki-page. Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 18 I/O ports at 01f0 I/O ports at 03f4 I/O ports at 0170 I/O ports at 0374 I/O ports at 11f0 Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 01) Subsystem: Dell Device 043e but i guess it only needs linuxcnc to work. (extremely high, in the 200,k's) What could be the reason for this and how can I go about fixing it? Thanks! How Latency-Test Works. LinuxCNC pc tests, version 20200930, started 05. 3 to run a BF20 milling machine equipped with a Mesa 7i96s. Set the base period higher than the latency result shows, at least 20 to 30% higher. The main bad effects of varying latency on servo systems (and step/dir systems Unfortunately this ISO is based on the PREEMPT-RT patch and I have a high latency of 50000. This means the drive itself runs the current (torque) and velocity PI loops This means the drive itself runs the high speed loops and effectively does 4 KHz servo cycle if the latency of the computer is very low, the parallel port is fast (PCI plug--in I have installed 2. I have seen some Radeon GPU's doing bad stuff to latency too (see here for example). There is no reason an i5 or i7 can't have as good or better latency than a Celeron. tgz And I should emphasize that this is for an rpi4b and likely will perform poorly on an rpi3b, and that I don't have a latency-test other than the one that comes with LinuxCNC My monitor is a 1920x1080 Since I am not running LCNC with a base thread, use 'latency-test period' as i am new here in the forum i will begin with a short story about myself. This can be useful to get a feel for how frequent the high latency excursions are. Ethernet connected devices have higher latency but also don't require low latency since the step pulses are generated by hardware or software on the connected device, not Mesa based stuff. 0-18-rt-amd64) on DELL Optiplex 7060 (i5 8500/32GB Ram, Radeon R5 430) and I am getting Base thread or period is mostly used for parallel port machine control so for Mesa boards and some other controllers it is not required, those use just the servo period, so if you plan on using them type this in a termal: latency-histogram(1), latency-test(1), linuxcnc(1) Much more information about LinuxCNC and HAL is available in the LinuxCNC and HAL User Manuals, found at /usr/share/doc/linuxcnc/ . While I am typing this, the computer has been running for a few hours with the But running the LinuxCNC latency test on the Gigabyte gives "Max Jitter (ns)" around 3 million (3ms) for the "Servo thread (1. The only issue is that the latency is slightly high, which should be due to the kernel configuration not being optimized to the fullest. Numbers 10 times has high as would be The computer is a HP Z240 SFF Workstation (J9C02ET#ABU) with i7-6700 CPU. 2 on an old Dell Optiplex 380 with 4GB RAM and a pi@raspberrypi4:~ $ halrun -I halcmd: loadrt hal_gpio inputs=GPIO6,GPIO12,GPIO13,GPIO16,GPIO17,GPIO18,GPIO19 \ halcmd+: outputs=GPIO20,GPIO21,GPIO22,GPIO23,GPIO24,GPIO25,GPIO26,GPIO27 \ halcmd+: invert=GPIO20,GPIO27 \ halcmd+: reset=GPIO21,GPIO22 Note: Using POSIX realtime Anyway, I've tested it on the OPi5 with LinuxCNC and that doesn't work indeed, it did work on my other installation. Like a ninny, I didn't check the latency with the live CD before I installed it. 0°C, crit = +105. 07. USB wireless will mess up latency, actually I do all my latency tests without any wireless. deb (installable with gdebi) are available at this link: linuxcnc-uspace_2. 10 network and my local network is 192. LinuxCNC pc tests, version 20200930, started 20. M. For slower systems you can lower the servo thread rate, 2 ms works fine for many machines. A good proportion of the results quoted Using 4. Hi All, I'm having trouble reducing the latency on my computer. Welcome to the community maintained website of the LinuxCNC Project Notice the wiki password has changed: See BasicSteps Table of Contents. I think this is not A good phenomenon. , OptiPlex 9020M Bios version A14, dated 06/27/2017 Chipset: Intel Corporation 8 Series/C220 Series Harddisk is non-rotational, ie. 2 ms to run and the thread slept for about 0. When launching my linuxcnc config, the steppers gives a "thud" sound, as if the drivers are sending power Command for latency test is: su linuxcnc -c "latency-histogram --bbinsize 1000 --base 50000 --sbinsize 1000 --nox 2>&1 | tee 1613676081. lat &" Latency testing loop started jue feb 18 20:21:46 CET 2021, should end after jue feb 18 22:21:46 CET 2021 Unexpected realtime delay on task 0 with period 50000 Attached is a script that can be used to test latency on PC's and laptops intended for use with LinuxCNC The script is made by user "seuchato", all credits go Latency is how long it takes the PC to stop what it is doing and respond to an external request. I am using a USB wireless dongle. Worst case, the jitter will be Hello all, Long time viewer, first time poster here. I was seeing latency before adding the switch and I'm hoping since it's a physical piece of electrical hardware it won't add any latency issues. The computer has an in-built I219-LM ethernet adapter, that I read somebody else had issues with. ===== Keyboard & Mouse related data: Number of mice: 1 Mouse 0 : ImPS/2 Generic Wheel Mouse Mice attached to USB: Keyboards attached to USB: LinuxCNC related data: LinuxCNC version is: 2. The kernel/Ubuntu version and Linuxcnc version are not the same thing. About LinuxCNC - Description FixingSMIIssues - fixing SMI issues that cause high latency StepMotorWireIdentification - Stepper Wire Identification Diagnosing Hardware - Diagnosing Hardware Problems Try a PS/2 mouse and keyboard if you can, I have personally seen reductions in latency by using non USB keyboard and mouse, I use PS/2 myself rather than USB. 2. Toggle Navigation LinuxCNC pc tests, version 20200619-c ***** General info: LENOVO, 10A8S1BX0N Bios version FBKT75AUS, dated 04/01/2014 Harddisk is non-rotational, ie. 0-18-rt-amd64) on DELL Optiplex 7060 (i5 8500/32GB Ram, Radeon R5 430) and I am getting nasty latency spikes (300 us), while alt-tabbing or basically moving windows. 000 ns). 06. My Linuxcnc dedicated PC is old but I thought good enough for the task: I have a new Asus motherboard runnign EMC2. Again, let me know if there is anything you would like me to check. Low latency and a faster than normal Servo-thread will be needed. Additional tool to export config json to create LinuxCNC config templates for fast initial machine setup. The lower the latency, the faster you can run the realtime threads, and the smoother motion will be (and potentially faster, in the case of software stepping). If you were using other board, I think it will lead to some issue. I make a fresh install of the latest ISO with Debian 12 and Linuxcnc 2. I am using Mesa 7i97. For testing i use very often laptops with crappy latency to control a 7i92 and it does work properly even with latency of over 300000. 168. 001000s) Note: Using POSIX realtime ***** My linux kernel is 4. 0°C) Core 2: +46. (extremely high, in the 200,k's) What could be the reason for this and how can I go about fixing it? Thanks! Only specific processes are designed to request high-priority scheduling. 19. 4. I originally installed Debian 12 Linux CNC. 28, dated 08/12/2010 Chipset: Intel Corporation 5 Series/3400 Series Harddisk is rotational The amount of swap currently used is 0 ===== CPU related data: model name : Intel(R) Core(TM) i3 CPU M 330 @ 2. latency-histogram(1), latency-test(1), linuxcnc(1) Much more information about LinuxCNC and HAL is available in the LinuxCNC and HAL User Manuals, found at /usr/share/doc/linuxcnc/ . However, this shouldn't have a major impact. I tried to update EMC2 to 10. For Hello, Yes, yet another post on latency issues. Add the 11 µs latency to the 4. One way to check overall servo thread latency (including all I/O and all LinuxCNC component times) is by monitoring the servo-thread. 47-rt37-kona-rt kernel the latency is much better, and can run Linuxcnc through ethernet connected to a 7i92 for 2 days without latency issues. Hi! I have a working Debian 10 with Linuxcnc 2. 06 this is accomplished by doing this: Attached is a script that can be used to test latency on PC's and laptops intended for use with LinuxCNC The script is made by user "seuchato", all credits go Attached is a script that can be used to test latency on PC's and laptops intended for use with LinuxCNC The script is made by - Page 13 LinuxCNC Forum. E. But then you should remove that from the instructions. 2 on debian bookworm (kernel 6. LinuxCNC Forum. 000744, max=0. An adjunct to the standard latency-test latency-histogram plots the distribution of latency. Once I got it installed the latency was terrible. 9 with Debian 12 (bookworm) on a 'development' machine because I'm very interested in customizing qtdragon_hd with qtdesigner etc. Note that latency with Ethernet hardware will be somewhat worse that shown by the latency test 3. Any thoughts? Attached is a script that can be used to test latency on PC's and laptops intended for use with LinuxCNC The script is made by user "seuchato", all credits Core 0: +49. 2 compiled from sources. -Got LinuxCNC pc tests, version 20200930, started 28. If it is needed only enable it when not running linuxcnc. The lower the latency, the faster you can run the heartbeat, and the faster and smoother the step pulses will be. Have latency issues and you’re in a world of hurt. Mismatch between LinuxCNC thread and EtherCAT cycle times. Have that and everything else is a cake walk. Try a PS/2 mouse and keyboard if you can, I have personally seen reductions in latency by using non USB keyboard and mouse, I use PS/2 myself rather than USB. 1. org/docs Info report created by linuxcnc_info: The file: /tmp/linuxcnc_info. Another ESP32(Sx) can easily connect directly to the controller with ability to communicate with the LinuxCNC host. 081036, avg=0. So I could work very well. Large number of bins and/or small binsizes With no special configuration their latency figures are ok, but not amazing, even with relatively new, higher spec machines, so I was a little disappointed. Use the latency-plot if you suspect this might be the cause. I am completely stuck: Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. I tried everything from the wiki to lower the jitter, but nothing worked, also because Nexcom managed to remove every mentioned option from the BIOS. 10 With Ubuntu 8. On the same PC while I was using debian 10 I Latency is pretty bad, so try disabling Hyperthreading in BIOS first, then everything with power saving and C states. tmax I plan to test it with Linuxcnc using a Mesa 7i92TF and a Gecko G540 running a Taig 5023CR micro mill. However, it just dawned on me that the latency may not be a big problem for me as I'll be using a Mesa 5i25 card along with 7i76 or 7i77. Parallel Port FPGA Communication. 12. 3. 9. latency-histogram --sbinsize 400 --show (with 10 glxgear and misc other commands being run) rtapi_app:T#[01] assigned to cpus 4 and 5, respectively Latency-test comes with LinuxCNC, you can run it with 'latency-test' from the prompt. LinuxCNC and HAL should not be running, stop with halrun-U. DO NOT TRY TO RUN LinuxCNC WHILE THE TEST IS RUNNING. Parallel ports do have low I/O latency, but parallel port based CNC systems also require low latency since the individual step pulses are generated by the host computer. Toggle Navigation Remember I have a package that will b) rt-preempt isn't even near to be enough to work with the parallel port, unless a quad-core computer is available. But a $5 used Matrox video card solved the problem - LinuxCNC does not require bleeding edge hardware. This requirement is independent of the type of external hardware. When invoked, it creates a temporary directory /tmp/tmp. Low latency and high-speed wireless point-to-point peripheral connectivity. I got Linux CNC 2. Also latency is best with only one core in use, so that the data in use by the realtime system is always in cache, on that core, reducing latency. 8 ms. My Linuxcnc dedicated PC is old but I thought good enough for the task: Latency-test comes with LinuxCNC, you can run it with 'latency-test' from the prompt. We also confirmed that the latency-test and the rtai kern/latency test select cpu cores differently. Toggle Navigation Linuxcnc and Hal should not be running, stop with halrun -U. 10. Now, if I conclude that graphics card really helps managing latency, am I doing wrong or Add the 11 µs latency to the 4. 0°C) Core 1: +48. 05. Move around I don't know the pi well but developed the Debian 12 installer using the debian images and pioneered the approach Cornholio is using to make the Debian image. Please Log in or Create an account to join the conversation. 40GHz cpu cores : 4 stepping : 9 1. SYNOPSIS latency-test [base-period [servo-period]] DESCRIPTION latency-test runs a simple latency test http while LinuxCNC is running In case the spikes are at exact intervals, say every 5 or 15 or 30 or 60 minutes, USB devices that can not go into sleep mode when requested by the PC, usually WiFi or bluetooth or cameras. 0~pre3. 0~pre0_arm64). I have configured the parameters in PCConf wizard with the appropriate IP (10. USB wireless will mess up latency, actually I do all Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. <something> and makes it the current directory. zip If you want Latency is how long it takes the PC to stop what it is doing and respond to an external request. Hello there, actually i am having a high max jitter, i tried to run linuxcnc on my raspberry pi 4 and when i run the latency test i got values of servo thread LinuxCNC pc tests, version 20200930, started 28. Latency is still important on a servo controlled machine, but really low numbers are not as critical as with a parallel port software stepping machine like you are familiar with. The minimum system to run LinuxCNC and Debian / Ubuntu may vary depending on the exact usage. 5 µs, you find that the computer is sluggish, so you settle on 16 µs. can you please add a way to find out the IP address and gateway address and ping the gateway say 50 or 100 times and report the times? That would be helpful to point out some PC's having issues with new kernels and network cards causing loss of connection to controler boards. tmax parameters: halcmd show parameter *. 04 you can see that the average jitter is about 5000 ns, but Disadvantages: - Sensitive to the LinuxCNC computer’s latency - Limited inputs/outputs - Some PCI/PCIe parallel port cards do not work well or do not properly support the EPP mode (EPP mode is required for parallel port interface to Mesa / PICO cards). Overall, a usable laptop for machine control, especially with more I also leave speedstep on on most PC and laptops so not to have the processors running at full blast generating heat unnecessary, if the latency does not sky rocket. I'm at my wits end here with this PC. tmax parameter (this parameter is in CPU clocks) 3. The latency test is important when configuring a LinuxCNC system. BUGS Sadly it seems like a gamble to me whether you get low or high latency with new hardware. A trade-off with a slower servo thread is that the number of velocity steps during acceleration is lowered, but this is mainly an issue with high Hi MX_Master, So I've got linuxcnc up and running on my orange pi (installer script works extremely well, thank you for all your work on that) - I haven't actually connected it to driver/motors quite yet, but I ran the latency test and note that jitter/latency is still quite high. Date: Thu 25 Aug I then compiled and installed the latest version of LinuxCNC (linuxcnc-uspace_2. Hi all-I've been running 2. So latency would not be an issue unless it was high enough for the servo thread to run late. Thanks tommylight, I Have integrated this values in my spreadsheet. 8. I didn't get any errors just high numbers. Hello, Yes, yet another post on latency issues. 0ms)". Check if snd modules are loaded: No, good! Yes, may cause bigger latency. SYNOPSIS latency-test [-nobase] DESCRIPTION latency-test runs a simple latency test http://linuxcnc. Note that the latency test only checks dispatch latency, not hardware = memory or I/O latency which can be much higher than the dispatch latency. 2020 20:20:41 ***** General info: ASRock, To Be Filled By O. 2020 13:48:40 ***** General info: Dell Inc. Smart external hardware typically only uses the (slower) servo thread so its easier to meet the latency requirement than simple hardware Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. gb7c7ab5aa ===== Preparing for latency NAME latency-test - test the realtime system latency. As I have not found anything about this topic related to linuxcnc I thought that it might make sense to share the resulting scripts and confs and stuff Hello there, actually i am having a high max jitter, i tried to run linuxcnc on my raspberry pi 4 and when i run the latency test i got values of servo thread Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. Latency is how long it takes the PC to stop what it is doing and respond to an external request. 5 µs high time, and you get a minimum period of 15. Latency values were higher without isolcpus (which I never needed to use on the previous setup). , OptiPlex 790 Bios version A11, dated 12/30/2011 Chipset: Intel Corporation 6 Series/C200 Series Harddisk is non-rotational, ie. Large number of bins and/or small binsizes I have a new Asus motherboard runnign EMC2. 0us)" is a little better, maybe 2 million. 3-1+b2 but strange enough disabling those only resulted in HIGHER latency instead of lower, so I stayed with only disabling virtualization and left the rest in their default settings. While running the latency test with 8. 2 After Installing i checked Responsive, mobile compatible. If I dont touch anything, latency is consistent around 0 for minutes. So, if your system load is high while testing, you'll get probably worse latency because a) system is overloaded in the first place, and b) if the watchdog detects there are processes waiting too much, it will throw a warning, that by itself will make latency perhaps The Preempt-RT kernel may benefit from tuning in order to provide the best latency for LinuxCNC. iso from linux website and at first struggled with high latency issues -Original ISO was buggy and caused issues - A helpful member in IRC traced it back to raspberry pi. Ethernet latency will be quite a bit higher than indicated by the latency test. Debian bookworm, linuxcnc 2. txt can be posted to a forum or a web site like: pastebin. Please Log in or Create an account to . The weird thing, the one that did not work well had a Ryzen 5 3500 that has no hyperthreading, it had terrible latency! Even my Lenovo ThinkBook 14 G3 with Ryzen 5 5500 works nicely with LinuxCNC. Hi, this may be a dumb question, but before I go buying a new PC and rebuilding everything, I thought I would ask I have an older PC, and the hdd failed, so replaced it and while I was on, I upgraded to Debian 10 and now my latency has gone ballistic and I cannot even start the mesa config due to latency, and the stepconf config starts with realtime errors, no matter as i am new here in the forum i will begin with a short story about myself. 132-cip30-rt59 and when I run latency-test , servo-period 1ms just with 25us jitter. com in order to provide information about the linuxcnc system and configuration. 3 on Raspberry PI 2 trying to understand the different latency test First results screen shot of latency-test Second results screen shot LinuxCNC Forum. ---How it works?-It uses latency histogram to test and generate latency info, Latency is how long it takes the PC to stop what it is doing and respond to an external request. 70GHz" When I ran the latency-test, I found that its Max Jitter reached 14us (ServoThread 1ms), 23us (Base Thread 25us). latency-histogram looks like this: arvidb@debian:~$ latency-histogram - Page 2. What I do is manipulating the IRQ affinity. Also have a look at this: Attached is a script that can be used to test latency on PC's and laptops intended for use with LinuxCNC The script is made by user "seuchato", all credits go to him for the effort put into this. The changes helped somewhat. For LinuxCNC the request is BASE_THREAD that makes the periodic heartbeat that serves as a timing reference for the step pulses. LinuxCNC and HAL should not be running, stop with halrun -U. 1 ms is fine for most normal CNC machines, only very fast (say laser cutters) or devices with combined high acceleration and high precision requirements need a faster servo thread rate. My Image is Clone from my SD card. BUGS In some of the kernel traces we did, the servo thread took about 0. For Mesa Ethernet cards, the latency + transport time must be less than the servo period (normally 1 ms). driver=i915 latency=0 ===== Parallel port related data: number of parallel ports is 0 ===== Os and desktop related For LinuxCNC installations based on Ubuntu 9. I have done quite a bit of reading about other similar issues. With the release of the old bios or the latest the same thing happens. 0~pre0_arm64_deb. With the former RTAI kernel only about 27000. That brought it down to 500-700 µs. If I bang around, like writing this post they climb to 195K, 140K ns respectively. 1. PC-Mesa card communication is ok, tested both with ping and mesaflash tool. To get an idea of actual latencies take a look at the *. Yes, may cause bigger latency. I hope you guys can help me with these issues, or guide me to some hardware that works If you need additional information, i'll gladly tell you. After removal of graphics card latency returned back to 80,000~115,000ns. Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. I have a new Asus motherboard runnign EMC2. The For example if your machine is very slow and/or you don't need particularly great accuracy, you can probably get away with worse (higher) latency. Note that if you get high numbers, there may be ways to improve them. I tried a few things different in the BIOS and the like, but nothing I tried made any difference. I have to use the WICD (?) debian network control to disconnect/reconnect each time. I get really high numbers above 250000 just by starting Firebox or Glxgears. I get readings up to 345000ns of jitter on the base thread and 650000ns on the servo thread. Large number of bins and/or small binsizes Done, and I also updated the sha512sum for rt-kernel. In the manual Link: Yes I know that this kernel and the associated linuxcnc is experimental. 0°C (high = +85. NAME latency-test - test the realtime system latency. Once you’re at a stage where it’s stable and low enough you’re ready to start cooking with fossil fuels. Something else — You are receiving this because you authored the thread. 31. Although your kernel description listed at the top of the Latency Histogram, has rt in it, I'm not sure that it is actually a real-time kernel. 2021 02:30:43 ***** General info: Dell Inc. See the TroubleShooting page for more on this topic. Post the results of latency tests you have done on PC's and Laptops / Notebooks using the script downloaded from here: I installed Linuxcnc-2. (Currently, the machine is running on an old gaming rig with a i7 and pcie parallel port attached to the Gecko without any real issues. on board video seems to work OK for latency but has issue with on screen 'noise' at higher res/color depths : 1001253: 5044: 29867: 6203: eMachines ET1331-45 : Does the attached latency plot look even half way normal for a rpi4 ? I get jitter result of around 75000 after a 10 seconds or so. More information on the Latency Test is here. Do latency tests with latency-histogram --nobase --sbinsize 1000 --show That will show the excursions you se as colored lines on both sides of the histogram. Shutting down and cleaning uo LinuxCNC task: 44863 cycles, min=0. Bios version P1. I am using linuxcnc for more than a year now. 2021 18:56:59 ***** General info: Acer , Aspire 5740 Bios version V1. So, I'm currently running the latest build of LinuxCNC. 90 and above). 04 on my CNC system (stepper driven Shoptask). Intel N100 works great with Debian 13 (Trixie pre-release) and LinuxCNC 2. Conversely, if you have a very high performance machine with high accelerations and want the highest possible precision. I believe that g_ether is meant to tether from Linux to another device. tmax (these are in units of CPU clocks on X86) Last edit: 07 May 2022 21:59 by PCW. To specifically test the operation of the RealTime kernel, use the kernel latency test supplied with RTAI. In saying that don’t get caught up trying to chase down latency too much. So no point having a multicore processor, the Atom works best when the second core The FPGA hardware is just a means for facilitating the gathering and distribution of the data that Linuxcnc needs to do that. I would assume, you can get latency down, but first and since you do not have a parallel port, I'd test your PC as it is set up now. In that case, some 15-20 usecs latency could be expected using isolcpus=1,2,3 and a boot line longer than the That's pretty high indeed, did you try to disable as many as possible energy saving settings in the bios? Adding kernel parameters? Perhaps there is a bad ram chip, you could try to remove 2 of them, 32gb is a lot for I understand that latency etc should not be a primary concern when using a mesa card HOWEVER I can tell you after trying four computers (with all the usual tricks) and getting poor usability and poor latency, this pi appearing to just simply work is 10/10. Normally LinuxCNC servo systems are run with velocity mode drives. 002223, 159 latency excurs ions (> 10x excepted cycle time of 0. take a look at all the tmax values after running LinuxCNC for a long time: halcmd show param *. On some i have to turn it off. 7. The files . I get high latency test results whenever I seem to hit the hard drive (during the test, such as opening folders). I just installed Linux cnc If I run latency-histogram --no base --sbinsize 1000 and 3 glxgear windows, my LinuxCNC control threads can be quite sensitive to system latency and jitter Latency-test comes with LinuxCNC, you can run it with 'latency-test' from the prompt. Tuning may be done via the kernel command line, sysctl, and via files in /proc and /sys . how is the servo threads latency, here I am getting high latency errors, with your previous image! HI Taylorcmg, First of all. Basically the latency and access time cause overruns. Pinging 10. I got similar latency on my Core2 Duo - until I turned off "CPU EIST Function" (Enhanced Intel SpeedStep) in the BIOS. The important thing with Linuxcnc is stable low latency. When you try 15. I was able to connect to the Mesa 7i96s card and when I ping it I don't get any errors either. For LinuxCNC the request is BASE_THREAD that makes the periodic heartbeat that serves as a timing reference for the I am running linuxcnc 2. Possible reasons: 1. 04 installed from the LinuxCNC LiveCD I get a very high jitter (200. When I open the Browser run a utube video they jump to 90-130K which is only slightly better then without the changes. Now, while testing with actual control panel after complete wiring, the graphics card malfunctioned (temp above 60 Degree C plus monitor black out) and resulted a 49ms latency spike. 7 for years quite happily (and linuxcnc of one sort or another forwell, lets just say a very long time!), and I've recently installed linuxcnc 2. None of the MB i have with AMD cpu's can disable hyperthreading, but that does not matter as all but one preform perfectly good for use with LinuxCNC. 5 µs. Some people's jitter is around 4us, but mine is very high. Let the test run for at least 15 minutes (it has been suggested that the longer the better let it run for a day or overnight for instance) while you run glxgears or a similar application to stress the cpu. For example, one PC had very bad latency (several milliseconds) when using the onboard video. 2021 06:53:13 ***** General info: Dell Inc. I'd set the value in LinuxCNC to 120 -130% of the obtained latency data (courtesy Tommylight). Post the results of latency tests you have done on PC's and Laptops / Notebooks using the script downloaded from here: LinuxCNC Forum. Stepper systems in general require faster threads to generate step pulses than servo systems. 2. Latency test seems clear, the histogram is more puzzling. I am trying to understand how these tests are used and what I should expect to see. 8 on the x86 hardware. "Base thread (25. 2022 16:17:44 ***** General info: LENOVO, 10MQS36600 Bios version M1AKT52A, dated 12/24/2021 Chipset: Intel Corporation 200 Series/Z370 Harddisk is non-rotational, ie. My Mesa card is on the 10. For newer versions there is a graphical latency test and you can just click to start it, but on Ubuntu Dapper/6. The Latency Problem ***** This subject must be the single most vexed and most frequently discussed subject in relation to running Linuxcnc, on 2. Large number of bins and/or small binsizes Latency is how long it takes the PC to stop what it is doing and respond to an external request. My x86 CPU is "Intel(R) Core(TM) i3-6100 CPU @ 3. Large number of bins and/or small binsizes I´ve recently installed Linuxcnc 2. It is a shell script that may seem mysterious to neophytes. 10 (Karmic Karma) and above, however, the default boot manager is no longer classic GRUB but instead GRUB2 (confusingly, this refers to GRUB v1. (extremely high, in the 200,k's) What could be the reason for this and how can I go about fixing it? Thanks! Latency is how long it takes the PC to stop what it is doing and respond to an external request, such as running one of LinuxCNC’s periodic realtime threads. Large number of bins and/or small binsizes will slow updates. I think It would only work on the board with some SOC Board which is Orange Pi PC. 13GHz cpu cores : 2 A little bit more research on the topic of dedicating cpu's helped reducing the latency to the current value of less than 4000ns. , OptiPlex 9010 Bios version A13, dated 03/27/2013 Chipset: Intel Corporation 7 Series/C216 Harddisk is rotational The amount of swap currently used is 0 ===== CPU related data: model name : Intel(R) Core(TM) i5-3570 CPU @ 3. Hello, after reading posts about Intel D525MW I believe that buying this board was good idea:-) However, in my case measured jitter is too high - base thread over 130 000 ns (2 glxgears running for 4 hours). Toggle Navigation Possible Latency spike issues The problem I am having is trying to determine my max latency (besides being a noob) When I use either the integrated graphics or the ATI card and absolutely nothing running but whatever runs at boot with RAM in non-interleaved mode and the Latency-Test going my Max Latency starts out at (1ms)996100, 1600 and (25us) 27591, 2752 Hi folks. I have a newly installed system following the guide. If we leave dirhold at 1 (the default), then the minimum time between step and direction is the 16 µs period minus the 11 µs latency = 5 µs, which is not enough. Latency too high because you use a generic EtherCAT driver. When I run latency test by itself I get the following; Servo 2K ns Base 7K ns Which is much better. Latency has more to do with the motherboard and how it is configured. ddaecszh hkdj vvltz njufrc xbwb tbffz vmjck pnm xaxbw glay