In a multithreaded programming environment, lock contention on the heap is often enough a performance bottleneck.
Theoretically at least, the cream-of-the-crop solution for this problem is to have the scalable/parallel[izing] allocator be entirely lock-free. However, it seems to me that besides a few research papers (e.g. ), which do contain promising experimental results, entirely lock-free allocators haven't trickled down to production environments. I'd be glad if you could prove me wrong with counter-examples though. So what are the practical reasons for this slow (or non-existent) adoption of lock-free allocators? Note that more widely used scalable allocators like the one from Intel's TBB are not lock-free although they use fine-grained locks (cf p. 315 in ).
For what's worth, I also found a CMU student project/paper, claiming to have implemented a lock-free allocator that is "slightly better than [Google's] tcmalloc" on up to 64-cores. Another interesting point in that paper is that "llalloc in these tests is Lockless Inc.'s LockLess allocator, which isn't 100% lockfree (it has a lock around the global heap)". jemalloc and ptmalloc are also benchmarked in there.
 Michael, Maged M. "Scalable lock-free dynamic memory allocation." ACM Sigplan Notices 39.6 (2004): 35-46. I found an independent [re]implementation of Michael's algorithm at http://people.cs.vt.edu/~scschnei/streamflow/
 Huang, Xiaohuang, et al. "Xmalloc: A scalable lock-free dynamic memory allocator for many-core machines." Computer and Information Technology (CIT), 2010 IEEE 10th International Conference on. IEEE, 2010. Free version of the paper as MS thesis.
 Kukanov, Alexey, and Michael J. Voss. "The Foundations for Scalable Multi-core Software in Intel Threading Building Blocks." Intel Technology Journal 11.4 (2007).
 Alex Podolsky, Nah Lock: A Lock-Free Memory Allocator; apparently written in 2013 based on parent directory timestamps and the "S13" suffix in the course name.
 Gidenstam, Anders, Marina Papatriantafilou, and Philippas Tsigas. "NBmalloc: Allocating memory in a lock-free manner." Algorithmica 58.2 (2010): 304-338. Source code available for this one.
As a footnote, I see there are 4 pending close votes for this question, but I see none for Why have hardware-accelerated vector graphics not taken off?. It would be interesting if someone could explain why a question that could potentially be answered by somewhat objective performance numbers is more opinion based than one where the main factor is the market orientation of 2-3 big companies.