On Wed, 2007-07-25 at 08:54 +0200, M. Koehrer wrote: > Hi Philippe, > > as I have mentioned yesterday, I have applied your (first) patch to Xenomai > (I did not apply > the other additional patches).
The third one would be needed to run the same code against the trunk, due to some difference in CPU affinity management between v2.3.x and -devel, but I had no problem running the lockup test for six hours without it over v2.3.x. > And yes, my application was running fine without freeze in an > overnight test. Not only the tiny test application but also the complex real > time application that > was the root cause for everything. > That is really a great improvement. Will this fix end up shortly in a > maintenance version of Xenomai? > I would appreciate that as this is a severe bug that should have a fix > published as soon as possible. > Yes, it is already merged into the maintenance and -devel branch, and v2.3.3 will be released shortly, since this is indeed a deadly bug. > Thanks a lot for the excellent support! > No problem. The lockup test you sent did make a huge difference and actually allowed me to focus on solving the issue immediately, instead of trying to find a way to reproduce it first. Thanks for this. > Regards > > Mathias > > > Hi Philippe, > > > > I have attached this patch to my application. So far it looks really good. > > However, I leave my test running to be sure that it works. > > > > Regards > > > > Mathias > > > > > > > On Fri, 2007-07-20 at 14:16 +0200, Philippe Gerum wrote: > > > > On Fri, 2007-07-20 at 13:54 +0200, M. Koehrer wrote: > > > > > Hi Philippe, > > > > > I left my test running for a couple of hours - no freeze so far... > > > > > > > > > > However, I have to do some other stuff on this machine, I have to > > stop > > > the test now... > > > > > > > > > > > > > Ok, thanks for the feedback. I will send an extended patch later today, > > > > so that you could test it on a longer period when you see fit. > > > > > > It took me a bit longer than expected, but here is a patch which > > > addresses all the pending issues with RPI, hopefully (applies against > > > 2.3.1 stock). > > > > > > The good thing about Jan grumbling at me, is that this usually makes me > > > look at the big picture anew. And the RPI picture was not that nice, > > > that's a fact. > > > > > > Beside the locking sequence issue, the ex-aequo #1 problem was that CPU > > > migration of Linux tasks causing a RPI boost had some very nasty > > > side-effects on RPI management, and would create all sort of funky > > > situations I'm too shameful to talk about, except under the generic term > > > of "horrendous mess". > > > > > > Now, regarding the deadlock issue, suppressing the RPI-specific locking > > > entirely would have been the best solution, but unfortunately, the > > > migration scheme makes this out of reach, at least without resorting to > > > some hairy and likely unreliable implementation. Therefore, the solution > > > I came with consists of making the RPI lock a per-cpu thing, so that > > > most RPI routines are actually grabbing a _local_ lock wrt the current > > > CPU, those routines being allowed hold the nklock as they wish. When > > > some per-CPU RPI lock is accessed from a remote CPU, it is guaranteed > > > that _no nklock_ may be held nested. Actually, the remote case only > > > occurs once, in rpi_clear_remote(), and all its callers are guaranteed > > > to be nklock-free (a debug assertion even enforces that). > > > > > > For the migration issue, the RPI transitions have been ironed out to > > > make sure we deal properly with all the subtleties of the Linux load > > > balancer. > > > > > > Mathias, please let me know if the attached patch improves the situation > > > on your side. > > > > > > -- Philippe. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
