C++ memory allocation mechanism performance comparison (tcmalloc vs. jemalloc)

If I remember correctly, the main difference was with multi-threaded projects.

Both libraries try to de-contention memory acquire by having threads pick the memory from different caches, but they have different strategies:

• jemalloc (used by Facebook) maintains a cache per thread
• tcmalloc (from Google) maintains a pool of caches, and threads develop a “natural” affinity for a cache, but may change

This led, once again if I remember correctly, to an important difference in term of thread management.

• jemalloc is faster if threads are static, for example using pools
• tcmalloc is faster when threads are created/destructed

There is also the problem that since jemalloc spin new caches to accommodate new thread ids, having a sudden spike of threads will leave you with (mostly) empty caches in the subsequent calm phase.

As a result, I would recommend tcmalloc in the general case, and reserve jemalloc for very specific usages (low variation on the number of threads during the lifetime of the application).