On Thu, 2012-02-02 at 12:52 +0200, Raz wrote: > hey > > I am trying to understand why a user space MT process behaves in an > unexpected manner. > I have real time process, which executes most of its threads in RT priority, > and from time to time a task ( medium priority ) is executing without > trying to stop. > > There are times, that this task is hogging the entire process and no > other **higher*** rt priority > task is getting any cpu time. > > Linux is **not** getting hogged. when setting the serial console ( > irq/serial ) and its shell ( /bin/sh ) > to a higher priority linux is responsive. > > Observing the task list through ps command i can see that this task's > threads when > to un-interruptible sleep. > > Any idea why is it happening ? Some ideas, but I need a lot more information. > kernel is 3.2.0-rc5-rt8. Is this a x86 box? Can you run a trace on the task that is going berserk? Enable CONFIG_FUNCTION_TRACER in your kernel and do the following: # mount -t debugfs nodev /sys/kernel/debug # cd /sys/kernel/debug/tracing # echo <pid-of-berserk-task> > set_ftrace_pid # echo function > current_tracer # cat trace Thanks! -- Steve -- 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
