On 24.05.2012 13:21, D K wrote:
> Hello, > we are doing a project on real-time scheduling on multi-core systems. > Right now I am looking for the possibility of using Gem5 as a simulation environment for testing different scheduling policies for multi-core systems. > > For the simulation we need a minimum 4 arm cores. each running a minimum software with a main while(1) loop and an timer interrupt handler. You should be able to create some bare metal code that you run that would do this for you. You can read the CPU id out of the MPIDR register and create a little bit of stub code that maps the interrupt vector to your ISR and progams up one of the timers to interrupt the CPUs. > Inside the timer ISR, I call the schedule function which updates the next ready task to be executed according to some policy. > Inside the main loop,some dummy task will be executed. > > 1.I have got the simulation run the Linux kernel but I prefer to make a standalone scheduler with some dummy tasks to keep the system simple.Is there an example which illustrates such a minimum system? You could probably start with the bootloader code in boot/arm/. Assuming you fence off some areas for a stack for each code you should be able to run C code without too much effort. 2 > ockquote> > remote gdb support will work just the same with and without the kernel. order-left:#1010ff 2px solid; margin-left:5px; width:100%"> 3.Is it possible to select the arbitration policy of bus. for example to select TDMA or Round-robin and specify the parameters eg. time quanta for TDMA ?does Gem5 models AMBA bus ? > us to enforce whatever policy you wanted. > > 4.How do I program the timer such that it send timer interrupt to all cores. How is the mapping of timer ISR handled? Is there a documentation which exp /div> Depending on which timer you would like to use (SP804 or CPU local timer), they are documented on arm's website infocenter.arm.com. You'll need to configure the GIC to either broadcast the interrupt to all cores, or configure each interrupt to only interrupt Thanks, Ali Thanks in advance..
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