Hi,
On Thu Oct 22, 2009 at 21:26:13 +0800, Guanghui, Cheng wrote:
If i ajust the exception handler when the L4 thread is runnning in the
L4 thread but i try to trigger the exception ipc when the main thread is running in the L4eRTL thread, the ex_regs system call can't return and it seems it will be blocked in the kernel whatever i used "L4_THREAD_EX_REGS_NO_CANCEL" or not. Vice versa.
I don't quite get a clear understanding of what's happening from the description but maybe a thread is busy looping. Is some thread ready?
Now the L4eRTL with using exception ipc triggerred interrupt-handling could work. All the demos before i prepared in the RTLWS11 about l4ertl could work with this version, about : single l4ertl thread in single doman, double l4ertl threads in single domain, multiple l4ertl domains coexisting with l4linux. But obviously the booting l4linux is much slower when runnng l4ertl app comparing to last l4ertl version (lazy interrupt handling in l4ertl). In this place i describe the problem again and hope it could be useful for you. You know the L4eRTl could support multiple l4ertl threads in one l4 thread. But firstly there is one l4 thread responsible for some necessary initialization issues such as init_sched, init_time and init_signals which are necessary for l4ertl system. And then l4 thread will create a first l4ertl main thread which will execute the user space main function. And this l4 thread will run as the idle thread in the l4ertl system finally. If there is a context switch between l4ertl thread to l4ertl idle (l4 thread) the ex_regs_flags system call will be frozed.
Hmm, that rather sounds like the l4ertl threads should switch themselves by changing their stack. But if it works now it's also fine.
Later i fixed the ugly design and now there is l4ertl idle thread is also a l4ertl thread not l4 thread any more. The system could work. I reserved all the environments and codes which could cause this frozen. Maybe next time i could show you and you could debug it. The next step should be the implementation of vtimers. Because it is in the user space and i could try different timer source like RTC and HPET. Last time you mentioned HPET and i think it should be better than RTC because HPET is internal timer and it should be faster than external RTC timer. Right?
HPET is probably faster than that, yes. Basically you should be able to program the HPET in user-space and use this as a timer source.
Adam