topic Re: Multi-core shared memory problem in MPC5xxx

Multi-core shared memory problem

xiha — Tue, 25 Jun 2024 15:21:07 GMT

Now, my Z4 core is responsible for Ethernet communication and Z2 core is responsible for CANFD communication.CANFD has a shared memory for receiving data, and Ethernet has a shared memory for receiving data.So I used two mutex locks to protect these two shared memory Spaces.But it triggers a deadlock.The brief code is as follows:

When the z4 core main program obtains the can_mutex, the Z2 core main program also obtains the enet_mutex. Both cores then trigger an interrupt when the mutex is not released, and both are stuck where the lock was obtained.

If I am not clear, please tell me what else you would like to know.Finally, I would like to ask if there is any good advice for me.Than you very much!!!

Re: Multi-core shared memory problem

lukaszadrapa — Wed, 26 Jun 2024 11:37:52 GMT

Hi @xiha

yes, it makes sense that this does not work. Of course, the program will never leave the interrupt handler to finish the critical section in main function. You can do something like this in operating system between different tasks but not here. This must be solved on application level. For example, you can set just some SW flag in the interrupt handler and then build some state machine in main which can handle this.

Regards,

Lukas

Re: Multi-core shared memory problem

xiha — Fri, 28 Jun 2024 08:45:07 GMT

I've changed my plan to not use mutex.I have found that when using a shared memory area with two cores, it occurs that the cache is not updated. Using two locks solves the cache problem, but it deadlocks. My colleague used the assembly code msync to solve this caching problem, so I can not use the lock, thank you for your help