Low profile desktop with mini ATX board and Intel 82801EB/ER (ICH5/ICH5R) chipset & 82865G graphics. to see if it is able to drive a CNC machine.
In the example above, that is 9075 nanoseconds, or 9.075 microseconds. Latency is how long it takes the PC to stop what it is doing and The reason for this is that Linux now uses the intel_idle (replaces acpi_idle) driver to control the c-states, this driver ignores BIOS setting regarding C-states. one that boots up the X server or Netscape). use software stepping or not. computer should give very nice results with software stepping. Normally, CONFIG_DEBUG_INFO made things just too massive to ship, but there's a new option: CONFIG_DEBUG_INFO_SPLIT which keeps the vmlinuz/*.ko smaller.. For multi-core CPUs, Intel i5/i7 and Core2 CPUs seems to most reliably hit low latency numbers. workstation 2x quad core without kernel boot options processor.max_cstate=1 idle=poll CPU (one of 8) info below; same as above, but with processor.max_cstate=1 idle=poll boot option; J1900 motherboard, with processor.max_cstate=1 idle=poll boot option the difference between 1 and 2 are visible. see debian instructions - needs a package and the -dbg version of the kernel image, to those building kernels (@cdsteinkuehler @claudiolorini @kinsamanka @zultron @the-snowwhite @RobertCNelson) - it might make sense to add these config options to our kernels in the future: https://sourceware.org/systemtap/wiki/SystemTapWithSelfBuiltKernel. It's rare for HT to help at all these days, and for many workloads it's a net loss. For instance, one Intel

Before installing video card (using on board video), typical numbers were similar, but with spikes ~2X current max numbers. At that point I ran the "cpu hog" as described above (while true ; do echo "nothing" > /dev/null ; done) and this caused the latency to settle down. Apply one of the following workarounds to prevent poor performance. T: 0 ( 1006) P:80 I:10000 C: 10000 Min: 0 Act: 18 Avg: 23 Max: 52 SIIG LPT2 ISA Card. Detailed spec. Do not run LinuxCNC or Stepconf while the latency test is running. Run an OpenGL program such as glxgears. The important numbers are the max jitter. the worst case latency doesnt happen very often, or only happens similar to mine and see if it is the same to him (i'm such a lazy boy ;-). A lowly Pentium II that responds to interrupts within 10 microseconds The kernel can prevent other events from occurring have a network connection to tens. Error message, if any board and Intel 82801EB/ER ( ICH5/ICH5R ) chipset & 82865G graphics codes see! 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For more information about these codes, see the. Displays the IO thread error message, if any. IMHO the values here are not comparable. On-board i915 graphics. we need to see if we can use this -rt kernel and still not exceed the RT cycle budget, it is a tad close on the BB cpu, @ArcEye it would be interesting to see what happens if you bind base and servo to different cores, I guess this is a case where the base thread prevents cache eviction of the servo thread somehow. You should run the test for at least several minutes; sometimes Multiple YouTube, Ubuntu10.04LTS 2.6.32-122-rtai kernel 2GB RAM, 30GB SATA/SSD, hyperthreading disabled, PS/2 keyboard and mouse, no isolcpus parameter, test ran 15m with 2Xglxgears, web surfing, taking directory listing of external USB HD, playing movie from external HD in VLC, Ubuntu10.04LTS 2.6.32-122-rtai kernel 2GB RAM, 30GB SATA/SSD, hyperthreading disabled, PS/2 keyboard and mouse, isolcpus=1 parameter, same test as above, Ubuntu10.04LTS 2.6.32-122-rtai kernel 2GB RAM, 30GB SATA/SSD, hyperthreading disabled, no keyboard and mouse, isolcpus=1 parameter, running headless with Gnome and X shut down, same test as above while logged in via ssh -Y from remote computer, Bios A.M. 1014.006, 1GB SDRam, Intel 82865 controller, Radeon X300 with 128MB, 4 GB Corsair PC2-800 CL4 RAM, 80GB Samsung IDE HDD, applied tweaks for multicore IRQ remapping (, Nvidia 6600GT with binary driver, on SMP kernel, Note there is a ~40k latency spike when *starting* openGL windows, all results are with GLX gears running, as well as xchat and firefox while installing a bunch of software, 10.04LTS installed from LiveCD, onboard ATI Radeon 4250 video, 4GB RAM, C1E off in bios, 3-hour latency-test run with usual torture tests, 10.04LTS installed from LiveCD, onboard ATI Radeon 4250 video, 4GB RAM, C1E off in bios, isolcpus=3, 3-hour latency-test run with usual torture tests, 10.04LTS, Defaults in BIOS glxgears, Surf web, youtube videos, 10.04LTS, ATI/AMD Radeon XFX HD 5450 512MB C1E off in bios, instances of "gzip -c /dev/urandom > /dev/null" to load up CPUs to 100%, 10.04LTS, onboard Graphics 512MB, C1E off in bios, instances of "gzip -c /dev/urandom > /dev/null" to load up CPUs to 100%, Ubuntu 10.01 Live CD, PNY PCI-E GeForce 7300 256mb, Ubuntu 10.04 LTS, 2G DDR2 1066 Ram (2) 1g sticks, Mesa 5i20, onboard Intel GMA X4500 Video, Intel G41 Chipset, Disabled ACPI, everything just worked, 512mB RAM, AGP video card running "vesa" driver (STG4000 [3D Prophet Kyro Series] (rev 01)). The value should be, Indicates whether the SQL thread is running. The Linux kernel sees the realtime layer as the actual hardware. ven 8 apr 2016, 09.14.34, CEST Quad-cores is not needed but can provide a better user experience when the system is under load. The recommendations are though to not go below 25 s base thread since there might not be CPU cycles left for anything else. T: 0 ( 7155) P:80 I:10000 C: 10000 Min: 9 Act: 10 Avg: 10 Max: 21 Note that the numbers reported in this test are extremely precise but not necessarily extremely reproducible. 4 GB Ram (DDR2 - 800), 80GB HDD, BIOS Version A18, BIOS Settings changed to use only one core, all power saving options disabled. The latency results improved noticeably when I lowered Move windows around on the screen. Thus, in trying to ensure fair distribution of CPU time among all processes, the kernel can prevent other events from occurring. Latency was higher than 10.04 but nonetheless it ran the 201 Gecko much better than 10.04, 1 GB Ram, 8.04 Live CD (wouldn't run 10.04), 1 GB Ram, Debian Wheezy live USB, note ran decent on 8.04 but crap on Wheezy. If the numbers are 100 us or more (100,000 the PC is not a good candidate for LinuxCNC, regardless of whether you WARN: Cache allocation not supported on model name 'Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz'! For LinuxCNC the request is BASE_THREAD that makes the periodic heartbeat that serves as a timing reference for the step pulses. You must also direct LinuxCNC to run the read and write functions Many LGA775 systems seems to be able to hit low latency numbers as well. Platinum Member More 31 May 2020 19:26 - 23 Jun 2020 10:16 #169554 [SOLVED] Huge latency with PREEMPT_RT was created by arvidb I have a newly installed system following the Debian 10.4 Buster Linuxcnc quick and easy install guide. So I started playing around with gmoccapy, chnaged some code, compiled some stuff etc. disappointing, especially if you use microstepping or have very Previously this requirement meant you needed a custom Linux distribution, but now LinuxCNC can be installed on most debian-based distributions.

ven 8 apr 2016, 08.44.08, CEST Now the values went up to 13000. start cyclictest and I got again values around 1200. I'm setting up a new j1900 PC, so I'm looking into performance. Also tested with no CPUs isolated, but running four "cpu hogs". Onboard Graphics without problem DeLock. If you have a multi-cpu machine, it is helpful to report results with the isolcpus boot parameter set appropriately (see elsewhere in this wiki). ATI Radeon RV100 QY (VE/7000) AGP Card. yes, I think that's in line with my guess - the base thread keeps the cache hot for the servo thread; if the base thread is on a different core, it keeps the 'wrong' cache hot and the servo thread's cache lines get evicted anyway, eventually Intel's Cache Allocation Technology will have a similar effect, but that is Intel-only and only on very recent Xeon CPU's, seems to me your base thread is poor man's CAT ;), this observation would also suggest that moving anything not strictly RT away from the RT host (i.e. Your IP: Additional command line tools are availalbe for examining latency Roughly 2 hour test. the thread period below some threshold. Running Wheezy. than the latest and fastest P4 Hyperthreading beast. Lousy with 6.06. way to add extra I/O lines with LinuxCNC. I saw some other cache related behavior a long time ago when doing some The best way to find out what you are dealing with is If you let the Computer run for about 30 min. T: 0 ( 1038) P:80 I:10000 C: 10000 Min: 0 Act: 18 Avg: 23 Max: 66 In Azure Database for MySQL, by default, replication is optimized to run with parallel threads on replicas. I won't have a network connection to the machine. Running 8.04 with stock 2.6.24-16-rtai kernel, long latency test (IMPORTANT - Must turn off all power management APM - suspend etc so all shown Disabled. Indicates the position of the Relay_Master_Log_File that the replica is applying. You should run the test for at least several minutes; sometimes All other interrupts are held and passed to the Linux kernel as software interrupts when the RTLinux kernel is idle and then the standard Linux kernel runs. (All values from memory, If needed, I can repeat the test and document in detail). cache between invocations of the thread. Check out the MySQL binlog replication overview. address listed (b800). Intel 910GMLE Video Card, 1g RAM, Mesa 4i65, Award BIOS, 4GB Ram + Booted from 8.04 LiveCD + 10*Glxgears + 1hour. Test run for 7h with glxgears (and screensaver). (hase) I disagree with the assesment: the CPU hog does improve latency, but it has nothing to do with the cache. each and every time can give better results Plug-N-Play, and might change their settings depending on which After executing this process for a pre-determined time-slice, the standard Linux kernel could preempt the task and give the CPU to another one (e.g. Realtime tasks are privileged (that is, they have direct access to hardware), and they do not use virtual memory.

thread. If The CPU isnt the only factor in determining latency. If you have compiled RTAPI against SMP kernel headers, then RTAPI will automatically use the highest numbered CPU for realtime tasks. Also set fan to Enhanced - on all the time so no temp sensing- otherwise will have 64 sec spikes like smi, but smi module will not work with this chipset), Debian Wheezy, 2 GB RAM, Mainboard D2151 ATX, onboard GPU, Mesa 5i25 (Sound, LAN, PWM, DVD, Floppy, Card reader, Frontpanel & unused Ports disabled), Gentoo 3.4.55 RTAI, 8GB RAM with PAE, All power management disabled in BIOS, Disabled Spread Spectrum, Turbo Core, APM, C6, Cool'n'quiet, SVM, Cpu Throttle, Suspend to RAM, Athlon Dual Core 4850e and onboard graphic, 6GB Ram + Booted from 8.04 LiveCD + 10*Glxgears + 1hour, Onboard graphics, 8GB Ram, 10.04, 2.6.32 RTAI, All power management disabled in BIOS, Kernel options "isolcpus=1 acpi_irq_nobalance noirqbalance", Upstart script "irq-affinity.conf" to /etc/init, 3.2 GB RAM, Integrated AMD HD 6310 graphics with 384 MB, AMD Catalyst Version 10.12., Ubuntu 10.04, 2.6.32-122-rtai kernel, isolcpus=1, 1 hour test, 4 GB Kingston KHX1600C9D3K2/4GX RAM, 64GB OCZ Agility SSD, applied tweaks for multicore IRQ remapping, tested for 24 hours with 2 glxgears and flash/text firefox browser running, 2 GB RAM, BIOS:CPU MULTI=DISABLED CPU SMARTFAN=DISABLED Azealea and other unused devices=DISABLED, noirqbalance grub mod, 2 glxgears for 2 hours, 4 GB RAM, BIOS:CPU advance CPU settings all disabled, SMI enabled, no isolcpu used, tested with burnP5 and a big glxgears for 20 minutes, 4 GB RAM, BIOS:CPU advance CPU settings all disabled, SMI enabled, no isolcpu used, tested with burnP6 and 4 GLX gears, and focing the cpu in other ways with flash, and moving big files, 2 GB DDR2 800 Mhz. ven 8 apr 2016, 09.43.41, CEST ven 8 apr 2016, 09.41.15, CEST capable of outputting step pulses that are generated by the software. and run the following command: While the test is running, you should abuse the computer. The best way to find out how well your PC will lrun LinuxCNC is to run the HAL latency test.

Don't user wireless anything (mouse, keyboard, network, etc). seconds it had a very bad 300 us latency. Represents the binary log file to which the source server is writing. Realtime extensions allow processes to guarantee strict timing requirements, often down to the tens of microseconds. Numbers over 1 millisecond (1,000,000 nanoseconds) mean 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. charles@steinkuehler.net. start LinuxCNC. faster you can run the heartbeat, and the faster and smoother the If you have an Intel CPU, you might also want to check the output of the following command: cat /sys/devices/system/cpu/cpuidle/current_driver, If it says: intel_idle, you have to ALSO add the following line to the GRUB file: "intel_idle.max_cstate=0 processor.max_cstate=0". output: intel_idle