On Tue, 2007-08-07 at 10:27 +0200, John Sigler wrote: > Daniel Walker wrote: > > > John Sigler wrote: > > > >> Would anyone care to comment? > > > > I'm not sure if this is the answer that you're looking for, but yes you > > certainly will find fixed bug is older version of the tree. > > I am not a kernel hacker, therefore I can only imagine how complex it is > to bring real-time to Linux. For some reason, I had come to believe that > the case of a single CPU without dynticks had been "solved" in the more > recent kernels (say 2.6.20), and that development had moved on, and was > now active in more "complex" areas like SMP/multi-core, dynticks, etc. There is always a chance of something not working, or a regression getting introduced in any of the code .. -rt is all still a development tree too, so it may not always be stable. > >> Perhaps I could also test a different strategy, such as xenomai? > >> http://www.xenomai.org/ > > > > If it's a kernel bug it's not going to matter if you use a xenomai skin > > or not.. If you use some other real time layer that might fix it .. > > *If* it is a bug in the -rt patch, then Adeos/Xenomai coupled with a > vanilla Linux kernel should not be affected by the same bug. Unless my > logic is broken somewhere. I wouldn't think so, but then what if Adeos/Xenomai has a new bug? > > you really need to test your app on a current version of the kernel .. > > We as developers generally don't support out dated trees.. > > This is the part I don't understand. I work for a tiny company with > limited resources. It's infeasible for me to track every new kernel > release and upgrade every time. I need to pick a kernel version that has > the functionality we need, test it thoroughly with my app, and then > never touch that kernel again. Ok .. > Unless I am mistaken, some people (like Thomas) have been deploying > systems based on PREEMPT_RT (or just -hrt) in indutrial settings for a > long time. (As far back as 2.6.15?) Obviously many bugs have been fixed > since then, which means that these versions contained many bugs. It's not a stretch to imagine. These real time chance has already been included in commercial distros, and are generally getting made into various products right now .. Just like what your doing . > How does one react when an important bug in found in a system that is > already in the field? Do they provide a way to upgrade the kernel (like > consumer-grade network routers)? Do they replace the complete system? I don't really know the details of this , but I would imagine there is some sort of upgrade path for say routers .. I've heard people talk about cell phone upgrading their software over the air.. It would be a difficult proposition to say make some specific kernel static forever .. Even the mainline stable kernel has bugs that get fixed.. Daniel - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html