using std::mutex and std::cond_variable inside enclave

Hi, I am trying to enable multithreading inside the enclave. What I do is to create a thread (by std::thread) outside the enclave and make an `ecall` into enclave. And inside the enclave, I use `std::mutex` and `std::condition_variable` to control the data access. But it turns out the program runs much slower than the single thread.

My question is whether sgx support `std::mutex` and `std::condition_variable`. Also, if the `TCSNum` is lower than the actual number of created threads for enclave, what will happen to these threads?

Thanks