On Thursday 21 January 2016 18:37:39 Bruce Layne wrote: > I hadn't seen this mentioned on the list, but maybe I missed it, or I > read it and my old brain forgot. > > I had a few old used PCs that I purchased for LinuxCNC 2.5.x. I ran > the latency test before buying them and the results were fairly good. > Then I decided to standardize on Atom motherboards for all of my > little CNC projects. I donated a PC to a friend, he installed > LinuxCNC 2.7 from the latest LiveCD and had horrible latency issues. > I made a LinuxCNC house call and saw maximum jitter greater than > 500,000 ns. We did the updates to everything and the jitter dropped > to around 12,000 ns, a little better than I originally saw with > LinuxCNC 2.5.x. His little C-Beam Machine desktop router is now > humming along nicely (and noisily). > > I'm a little interested in why the latency was so bad before updating, > but mostly I posted this so people would know to run the updates > before doing the latency test, and would realize that running the > latency test from the live version running off a USB drive wouldn't be > a proper test of whether a PC is a good candidate for LinuxCNC. > This walks and quacks like the nvidia driver duck, which locks out interrupts for 100's of milliseconds at a time when its even remotely busy. The card can probably be driven by the nouveau driver, which does not abuse the system to nearly that extent. The fallback vesa driver could be the acid test if you can coax it into running that in place of the proprietary nvidia driver. If the latency then is good, then see if you can make it switch to the nouveau driver. Its not a gamers driver, but its plenty good enough to show you what linuxcnc is doing in real time. > > > > ---------------------------------------------------------------------- >-------- Site24x7 APM Insight: Get Deep Visibility into Application > Performance APM + Mobile APM + RUM: Monitor 3 App instances at just > $35/Month Monitor end-to-end web transactions and take corrective > actions now Troubleshoot faster and improve end-user experience. > Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
