Minimizing the amount of malloc() calls improves performance?

Question

Consider two applications: one (num. 1) that invokes malloc() many times, and the other (num. 2) that invokes malloc() few times. Both applications allocate the same

Answer 1

These are of course implementation details, but typically free() will insert the memory into a list of free blocks. malloc() will then look at this list for a free block that is the right size, or larger. Typically, only if this fails does malloc() ask the kernel for more memory.

There are also other considerations, such as when to coalesce multiple adjacent blocks into a single, larger block.

And, another reason that malloc() is expensive: If malloc() is called from multiple threads, there must be some kind of synchronization on these global structures. (i.e. locks.) There exist malloc() implementations with different optimization schemes to make it better for multple threads, but generally, keeping it multi-thread safe adds to the cost, as multiple threads will contend for those locks and block progress on each other.