> -----Original Message----- > From: Gene Heskett [mailto:ghesk...@wdtv.com] > Sent: Friday, December 07, 2012 2:33 PM > To: emc-developers@lists.sourceforge.net > Subject: Re: [Emc-developers] xenomai on beaglebone : working > 3.2.21 kernelrunning Ubuntu precise, latency > > On Friday 07 December 2012 14:05:13 Jon Elson did opine: > > > Michael Haberler wrote: > > > it's the latency test which comes with the xenomai > userland support; > > > note this is for idle CPU > > > > > > running a compile over NFS this creeps up to 30ish > max/55worse while > > > still being around 12 average > > > > Well, average is not very meaningful for our purposes. 55 > worst case is > > not good for > > SW step generation, but probably acceptable for hardware-assisted > > systems. OR, > > for use with the PRU, which looks quite promising! > > > > > it's fixed at 720 Mhz, I took all the frequency scaling/power > > > management options out of the kernel config, in a previous kernel > > > build these were on and the result was much worse. > > > > Certainly no surprise! > > > > Jon > > > Silly Q, Jon & the rest of you hardware guru's. Has anyone > looked at the > possibility of using a propeller board for something like > this? With 8 > cores of what I see as a risc machine, it seems possible if > it wouldn't be > i/o bound.
The propeller works well for generating the steps. It works less well at communicating with a host if all comms would be consolidated in a single core for communication with the host. There are no hardware serializer/deserializer peripherals in the chip so everything has to be bit banged. We did try this and put it back on the shelf. Steve Stallings > > Or is this something that an arduino per channel would make a > better design > because I think I see that the propsticks output ports are > multiplexed, > probably at its clock speed, 12 to 50 mhz? This could create > jitter right > there. > > Cheers, Gene > -- ------------------------------------------------------------------------------ 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-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
