2012/12/12 Gene Heskett <ghesk...@wdtv.com> > > > I will say it. If its a 64 bit install, then it is not the rtai patched > kernel, and the results predictably will be poorer. > > Read my post again. There are two different PC's involved in my tests. One is now installed with 64 bit Ubuntu - not LinuxCNC. The other one is installed with LinuxCNC.
> Neither of my machines has ever exceeded 8u-s, with only one stick of > memory in them, 2Gb IOW. Latencyplot has been running on the lathes > machine for about an hour, base-thread peak is 5 u-s, servo-thread peak is > 5 u-s. > Well, good for you and I would be glad to share that experience. But the fact remains, I have two D5252MW's and none of them have been close to your levels. Did you push the hardware? Did you start a download, a browser, glxgears? if I let it idle of course it will look good. That is not realistic though and as I have stated earlier it's enough to start a Firefox to totally destroy the figures. Looks a lot better now when both memory banks are used, still double up from your latency. I wonder if this board has changed too much over releases, maybe we don't have the same hardware if we dig into the board itself. > > > I don't think you changed the graphics driver just by lowering the > > latency. I have not done much Linux stuff in years, but I'm wondering > > what X graphics driver you are using? Can you force the graphics driver > > into some VGA totally software render mode? > > > > Also remote into it, and run it as a headless station. I should do this > > and see how it performs. Maybe next time I have a few hours around the > > house (hah! not in the next few weeks…) I'll run that test. > > > > > One thing though, I filled one of the boards with 8 GB RAM (2x4). That > > > board is running 64 bit Ubuntu in the office and it happily reported 8 > > > GB even though the hardware spec says max 4 GB. It seems that 4 GB is > > > a soft limit. > > > > Running a 32 bit kernel? I don't think you'll be able to address over 4g > > via sw. Maybe they expect people to run windows, not Linux! > > > > Interesting that you can put the RAM in, as like you, I had assumed that > > it was not just a SW limit. > > > > Thanks; > > > > John A. Stewart. > > A 64 bit linux that has a problem with even 64Gb of ram should have a bug > report filed. 32 bit however has to jump through some time consuming > hoops. > > I wrote soft limit. Not software limit. The board specification says max 4 GB RAM and it can be rewritten into "is only guaranteed to work with 4 GB, but can handle more on your own risk". The board itself is a 64 bit architecture. The software limit theoretically for a 64 bit system is 2^64 bytes (16 exabytes). I have a bunch of blade servers at the office with 300+ GB RAM. I did the remote test earlier (also reported to this list) and the figures are better. Have in mind that half of this list will stupidify you if you suggest running two PC's at the same time. The graphics driver of this board share memory with the OS, when going down in resolution it will affect the memory usage. The desktop also becomes a bit more responsive but looks like crap in the lower res when the same monitor is used. Nevertheless it was no real performance impact. I can watch HD video on my cell phone but not on these PC's. Probably they will be used as automation controllers, end up in a CNC cabinet will not happen. Regards, Sven ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
