On Sunday, January 08, 2012 07:25:36 PM Kent A. Reed did opine: > Gentle persons: > > Recently, I wrote... > > > I just ran 15-minute latency tests on my ASUS AT5NM10-I board (which > > is equipped with an Intel Atom D510 cpu) first with a stock boot and > > then with isolcpus=1 as a boot parameter. I've posted my results in > > the table on the Wiki. > > > > In brief, isolating one cpu shaved approximately 6000ns off the max > > jitters reported for both the base thread and the servo thread. > > > > Of course the latency test should be run much longer but I believe > > these numbers are indicative. YMMV > > I had a few minutes this afternoon and decided to try another experiment > with this board---still running Ubuntu 10.04LTS with the > 2.6.32-122-rtai kernel. > > I disabled Gnome (which shut down X) on the board by running the > following from the command line: > > sudo service gdm stop > > (I disabled a few other services too, like Apache, but I don't think > this is relevant. The stock Ubuntu/EMC2 install starts up far too many > services for my taste. When I want a controller, that's all I want, not > a desktop computer.) > > Then I logged out and disconnected keyboard/mouse/monitor (well, > actually I just set my KVM switch to another computer; possibly it > still imposes some electrical levels at the motherboard connectors.) > > Finally, I logged into the board via Ethernet from another computer > using ssh -Y and again ran the latency-test for 15 minutes with > approximately the same level of stress as before (2 copies of glxgear, > web browsing, listing the directories of an external USB drive, etc.). > > Bottom line: the latency numbers got even better. Max jitter fell to > 3211ns/3222ns. > This is sounding better all the time Kent. I intend to do something similar in terms of comfortable code writing by using my laptop as the console. Unforch, I would have to move it quite a few feet closer to the mill to make headless useful & that would expose the lappy with its known fragile keyboard to many times the dust and dirt it would see in its present location about 8-9 feet away. However, with care & some additional remodeling it might be doable. A warmer weather project for sure.
> For some time I have envisioned running my tabletop mill with a headless > controller and a networked operator console. If anything, the present > result says this would be the preferred mode. Of course, I could make > it cleaner by stripping down the distribution some more, possible even > install RTAI and EMC2 over a Ubuntu server distribution to avoid the > Gnome/X-server stuff altogether, since there's the usual niff-naff > about booting Ubuntu desktop edition without a monitor attached, etc. > > I'm curious if anyone has tried this experiment with other boards and, > if so, what results were obtained. > > And, yes, I realize I am chasing after diminishing returns. The latency > on a stock board is already good enough for practical purposes. Let's > just say my home situation causes a form of ADHD were I work furiously > on very short-term projects. Understood Kent, our sympathies are with you. 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) My web page: <http://coyoteden.dyndns-free.com:85/gene> Serving coffee on aircraft causes turbulence. ------------------------------------------------------------------------------ Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
