Efficiently allocating many short-lived small objects

Question

I've got a small class (16 bytes on a 32bit system) which I need to dynamically allocate. In most cases the life-time of any given instance is very short. Some instances may also be passed across thread boundaries.

Having done some profiling, I found that my program appears to be spending more time allocating and deallocating the things than it's actually spending using them so I want to replace the default new and delete with something that a little more efficient.

For a large object (db connections as it happens, which are expensive to construct rather than allocate), I'm already using a pooling system, however that involves a list for storing the "free" objects, and also a mutex for thread safety. Between the mutex and the list it actually performs worse than with the basic new/delete for the small objects.

I found a number of small object allocators on Google, however they seem to be using a global/static pool which is not used in a thread safe manner, making them unsuitable for my use :(

What other options have I got for efficient memory management of such small objects?

Answer 1

Maybe try using Google's tcmalloc? It is optimized for fast allocation/deallocation in a threaded program, and has low overhead for small objects.