On 5/6/2013 9:16 AM, Lars Segerlund wrote: > check the data on osadl.org ... with RT-Preempt you should be able to > get worstcase jitters of less than 50 us ... or you have a 'bad' > system / bad drivers. > > With a 'good' RT-Preempt system you get < 20 us as worstcase. > > osadl is good since they are really hammering the systems while measuring. > > / regards, Lars Segerlund. >
Lars: I'm not looking to open a discussion about the definition of jitter and the appropriate methodology for measuring it (we've had some of those in the past on this list, and some of us are quite familiar with OSADL). What I'm looking for is better guidance to our CNC users, most of whom find the details about latency as understandable as details about the fuel-injection algorithm used in their car's computer. What we have seen in the time I've been reading the emc2- lists amounts to constant schoolyard taunting, "my latency is better than your latency." Look how excited we get when the latest Atom board yields 1us lower or higher jitter results than another. If the better guidance includes pointing to the OSADL as another source of data (along with suggestions on how to interpret those data) so much the better for the folks who wish to use RT-PREEMPT enabled kernels (and my thanks to those on this list who have been making it possible for the average user to even consider using them). Regards, Kent ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
