Check `src/mpid/common/thread/mpidu_thread_fallback.h`. MPID_THREAD_ macros are defined to the `MPIDU_THREAD_` macros. This is to allow device override of locking mechanism. At some point, you may need look at `src/mpl/include/mpl_thread.h`, which is where the actual mutex being defined. -- Hui Zhou From: Yongyu Chen via discuss <[email protected]> Date: Tuesday, February 2, 2021 at 10:34 AM To: [email protected] <[email protected]> Cc: Yongyu Chen <[email protected]> Subject: [mpich-discuss] Question about counting the mutex waiting time Dear sir or madam, I’m currently working on a project with mpich. I faced some difficulties when I would like to count the mutex waiting time, just like what they did on the paper, Fine-Grained Multithreading Support for Hybrid Threaded MPI Programming. I could not find the definition of the function, MPID_THREAD_CS_ENTER(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX). If you could provide me more detailed information, I will appreciate it. Thank you in advance! Sincerely, Yongyu Chen