That looks pretty nice. My J1900 board is only around 10us running RTAI. Maybe I'll have to give it a try.
But can a Preempt-rt kernel pull off acceptable latency scores (50-100us) on old hardware? Such as the old P4 box (with ISA slots) I have that runs great with Lucid (20us), but I can't get the Wheezy RTAI Kernel to work on it at all. ----- Original Message ----- From: "sam sokolik" <[email protected]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Tuesday, July 4, 2017 6:33:10 PM Subject: Re: [Emc-users] Maybe we don't need rtai anymore? This image got stripped http://electronicsam.com/images/KandT/testing/user-04Jul2017-1172.png sam On 07/04/2017 05:22 PM, sam sokolik wrote: > I have been playing with linuxcnc for a long time... It has come a > long way. > > Currently the RTAI folks seem to have issues developing. > > Now there is RT_Preempt. Couple cool things.. It has been migrated > to the linux foundation. This means a lot eyes on it. It is also > pretty easy to build. I have done it quite a few times now. My > experience is that the out of the box rt_preemt has ok realtime > performance. Anywhere from 20 to 100us latency. Perfect for > external interface cards (mesa, pico and such). I have a computer > that has decent enough rt-preempt performance that it is running 50us > base thread. (small emco lathe - 100 line encoder for threading) I > have been running this for quite a while this way with no issues. > > Why am I rambling... > > Well - I have been playing with debian stretch and 4.9.0-3-rt > kernel. I booted our matsuura (j1900 quad core) which with no > tweeking has aprox 100us latency. (it has been running mesa ethernet > cards with rt_preempt - no issues) Next I booted it with some kernel > line tweaks. (checking the hardware - processors 0,1 and 2,3 share > cache. So I added > > isolcpus=2,3 idle=poll > > The latency on this system was phenomenal. It has been running for > hours now and still <6us > > > > these numbers are as good or better than rtai. Could we, with some > tweaks, use rt_preempt for printer port configs and forget about rtai > for now? I have more computer hardware I can test - but this is > pretty awesome. > > Good video explaining realtime > https://www.youtube.com/watch?v=BKkX9WASfpI > > Rt-preempt even runs decently on my laptop. I have actually run test > and real machines with it. (don't mute the speakers though... causes > huge spikes) > > sam > > ------------------------------------------------------------------------------ > > > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
