In multithreaded C/C++, does malloc/new lock the heap when allocating memory

Question

I\'m curious as to whether there is a lock on memory allocation if two threads simultaneously request to allocate memory. I am using OpenMP to do multithreading, C++ code.

Answer 1

Free store is a shared resource and must be synchronized. Allocation/deallocation is costly. If you are multithreading for performance, then frequent allocation/deallocation can become a bottleneck. As a general rule, avoid allocation/deallocation inside tight loops. Another problem is false sharing.