From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4443AB1F.2060405@domain.hid> Date: Mon, 17 Apr 2006 16:50:07 +0200 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-help] General question on Native Skin tasks References: <6ee4c8380604161110y3c937a74t9186bad2d9af2058@domain.hid> <4443992C.5000808@domain.hid> In-Reply-To: <4443992C.5000808@domain.hid> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: xenomai@xenomai.org, "Brian L." Jan Kiszka wrote: > Brian L. wrote: > >>If I create a native-skin RT_TASK from userspace with no flags, i.e. >> >>void task(void*) >>{ >> for (;;) ; >>} >>int main() >>{ >> RT_TASK t; >> rt_task_create(&t, 0, 3, 0); >> rt_task_start(&t,task,0); >> (do something which blocks) >>} > > > mlockall left out for simplicity? Or is it also missing on your real > test? In the latter case, occasional application crashes are "normal" > (as described below). > > Philippe, you suggested some code for detecting this. We should really, > really add this soon (maybe to the exception path)! > The submitted patch works pretty well detecting unlocked memory, I'm using it right now, but I'd like something a bit more self-explanatory than just receiving SIGXCPU. I don't think the execption path is the right place to put this, since the mlockall issue causes random bugs, and you likely want to detect them early and unconditionally. > >>Should that task starve all other tasks? In what ways is it different >>behaviorally from an ordinary posix thread? I ask because I have a >>thread that might be spinning and a frozen system (back in the rtlinux >>days, spinning in the real-time domain was a surefire way to freeze >>without any other sign of trouble). If it is the case that this task >>outweighs an ordinary linux thread/task, how can I make it the same? > > > A task that has high priority than other system tasks has to outweigh > them. This has nothing to to with POSIX (standard Linux included!), > RTLinux, Xenomai, or whatever. But Xenomai has a simple watchdog to > recover from run-away RT threads. > > >>Also, I haven't completely tracked this down yet, but xenomai seems >>to be page-faulting in a loop and exploding rather spectacularly in a >>native-skin multithreaded program that doesn't do anything outside of >>relatively ordinary queue/mutex/task stuff. I'm upgrading to trunk to >>see if it goes away. >> >>Short of a serial cable, is there a way to capture Oops/Panic text as >>it flies by? > > > linux/Documentation/networking/netconsole.txt is another option. > > Jan > -- Philippe.