On Tuesday 18 March 2008, John Kasunich wrote: >Gene Heskett wrote: >> In re the rtapi and unexpected realtime delay issues, I experimented some >> this afternoon with my base thread which was set at 78000ns when I >> started, reducing it to 38000ns for the last test, running most of the >> stuff in the nc_files dir to test, and never did see another error AFTER >> the startup, even when running at 200% speeds here. > >You never will. > >The realtime delay error message is printed only once, the first time >EMC notices a delay.
I have, once or twice, seen 2, but they don't coome from the same code, the windows it opens are different sized. But thats very rare. Both at startup, just as axis has finished drawing its screen, and many seconds before emc would ever be asked to do anything. >We don't print it every time because if you have >your period set too low, or you have a computer with bad realtime >issues, you could get hundreds or thousands of those messages every second. And a machine that could only be rescued by a tap on the reset button. Thats not a Good Thing(TM). OTOH, if the first thing you did after rebooting was to add 20% more time to the base_period, you would soon know if the hardware was usable for emc. >Only printing the message once solves that problem, but it means that >you really don't know how often you are getting a delay. But DON'T >think just because you get it only once that it is happening only once. > >Regards, > >John Kasunich Hummm, much food for thought, does it hit the logs or is that skipped too? Doing the test over an ssh -Y link, I see some decent numbers with a worst case n about 5 minutes of web browsing of 14500ns, 14.5 u-secs. I don't believe its that good running on its own screen, giving numbers in the 17800ns area IIRC. Still, even 20 u-secs is tolerable. The last time I ran stepconf, it chose a 78 u-second base period, which did seem rather slow. However since the advent of one cycle steps in the stepgen these days, the text is in bad need of updateing on the wiki page that discusses the latency-test and how to use it. That is at: <http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?TweakingSoftwareStepGeneration#Run_a_Latency_Test> Since it is assuming 2 cycles per step, the description gets confusing fairly quickly as I'm not sure what I should throw out to make it sensible in a one cycle step scenario. Its still running, and showing a base_thread of about 38500ns, and a jitter of just under 14000ns, so what would be the ideal base_period, ignoring the startup message that axis's drawing of its gui apparently creates? BTW, 2.2.4 'feels' good. No surprises so far, but then I haven't made any chips either as I'm still rebuilding that corner. I bought a 36x48 sheet of some sort of acrylic that is supposed to be 250 times stronger than glass, but in nibbling off a corner to use as the mount for the suicide brakes resistor (40 ohms), I found cracks propagate through it just like regular acrylic. Lexan it ain't.. Whats left will be placed on the frame between the mill and the computer, and the keyboard shelf will get wider so there is room for the mouse etc etc. I haven't figured out what to do with the ups yet, it is about 60 pounds & crowds the hell out of the shelf above the monitor where the xylotex and its psu live alongside the computer. 60 pounds that high in the air on a step stool is a bit much for this old fart these days. Thanks John. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Outside of a dog, a book is man's best friend. Inside of a dog, it is too dark to read. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
