#linuxcnc-devel | Logs for 2016-07-07

[06:08:20] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15andypugh commented on issue #107: I think that this also needs a manpage in docs/man/man9... 02https://github.com/LinuxCNC/linuxcnc/pull/107#issuecomment-231043974
[08:07:25] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15jepler opened pull request #108: Preview: uspace+RTAI (06master...06uspace-rtai) 02https://github.com/LinuxCNC/linuxcnc/pull/108
[08:49:36] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15tinkercnc commented on issue #108: Suggestion: ... 02https://github.com/LinuxCNC/linuxcnc/pull/108#issuecomment-231075637
[09:35:50] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15jepler commented on issue #108: @tinkercnc that would be a fine topic for a different PR, thanks. 02https://github.com/LinuxCNC/linuxcnc/pull/108#issuecomment-231088351
[09:38:50] <jepler> yay, description on pull #108 updated. silly github for eating my text in the first place.
[09:39:53] <jepler> tl;dr: uspace has to change just slightly to work with rtai-realtime but then there's a lot of boring work yet to do. latency looks pretty good, but I didn't stress it yet (or compare to what my system does with rtai realtime and linuxcnc with traditional kernel modules) https://cloud.githubusercontent.com/assets/1517291/16655638/e16a2c40-4420-11e6-8840-8dcf7e7324d7.png
[09:40:48] <cradek> does this loosen the requirements that the linuxcnc build and the rtai kernel match closely?
[09:42:10] <jepler> cradek: I'm not sure
[09:42:41] <jepler> I don't know if liblxrt.so has a stable ABI or not
[09:42:48] <cradek> there'd be no kernel modules except the rtai-provided ones, right?
[09:42:53] <cradek> oh hmm
[09:42:54] <jepler> yes that is true
[09:43:56] <cradek> sure seems likely to help
[09:44:38] <jepler> the part that would be dependent on rtai/liblxrt version is just one ~200-line file
[09:53:24] <jepler> the realtime script for loading/unloading those modules would have to know how to find the modules that match the running kernel (we install them such that 'modprobe' doesn't find them, more's the pity)
[11:46:19] <skunkworks_> Isn't there something about classic ladder only running at 1ms - no matter what the base thread is?
[11:46:34] <skunkworks_> *Servo thread
[11:49:03] <cradek> I remember that too, but I think it's no longer the case
[11:49:05] <cradek> what are you seeing?
[11:49:37] <skunkworks_> The post on the forum about the monostable acting funny
[11:50:09] <jepler> I didn't read every comment but https://github.com/ShabbyX/RTAI/issues/16#issuecomment-44211118 makes it sound like their conclusion is that lxrt abi is pretty stable
[11:50:27] <jepler> I think I have two different rtai kernels available on my test machine, I can try it for myself..
[11:54:42] <jepler> > At least earlier RTAI kernels provided by the LinuxCNC project have had kernel symbol versioning turned off, which allows kmodules built for one kernel to be inserted into a different kernel. IMO this is a dangerous thing to do, ...
[11:54:46] <jepler> hm did we really?
[11:54:49] <jepler> on purpose?
[11:55:49] <cradek> the mists of time make it hard to say for sure
[12:20:04] <skunkworks_> I know people are taking realtime modules (like linecurve) from linuxcnc and putting them on pathpilot without issues
[12:26:00] <cradek> I think pathpilot uses the linuxcnc rtai kernel on ubuntu10
[12:26:15] <cradek> so it's not surprising that modules from our packaged releases work
[12:26:38] <cradek> but I cry for people who do that kind of thing without using the packaging system
[15:40:05] <KGB-linuxcnc> 03Sebastian Kuzminsky 05master 660a629 06linuxcnc 10docs/src/code/building-linuxcnc.txt docs: fix a typo in Building LinuxCNC * 14http://git.linuxcnc.org/?p=linuxcnc.git;a=commitdiff;h=660a629
[15:40:05] <KGB-linuxcnc> 03Sebastian Kuzminsky 05master 092017b 06linuxcnc 10docs/src/code/building-linuxcnc.txt docs: more packaging info in Building LinuxCNC * 14http://git.linuxcnc.org/?p=linuxcnc.git;a=commitdiff;h=092017b
[19:43:10] <jepler> linux-image-3.16.0-9-rtai-amd64 doesn't work on my machine :(
[19:43:23] <jepler> so I can't easily test whether lxrt is abi-stable enough to work with that and 3.18-rtai
[20:42:40] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15jepler commented on issue #108: Now this works on systems that follow the linuxcnc standard (but debian-filesystem-layout non-compliant) system of putting rtai modules in /usr/realtime-`uname -r`/modules without any extra steps. 02https://github.com/LinuxCNC/linuxcnc/pull/108#issuecomment-231251915
[21:22:37] -linuxcnc-github:#linuxcnc-devel- [13linuxcnc] 15jepler commented on issue #108: and now it packages. Probably needs some more detection when the target is uspace and there is no rtai developement header available. (in fact, rtai-modules is currently a missing build-dep, hmm) 02https://github.com/LinuxCNC/linuxcnc/pull/108#issuecomment-231256874