Why replacing standard glibc malloc with Microsoft's mimalloc or jemalloc yields a 15-30% speedup in multi-threaded C++ applications:

• Thread-Local Heaps: mimalloc allocates pages per-thread, completely eliminating global heap mutex contention.
• Page-Level Free Lists: Sub-allocation within 64KB pages minimizes memory fragmentation.
• Drop-in replacement: Link with -lmimalloc or preload via LD_PRELOAD=/usr/lib/libmimalloc.so with zero code changes!

Benchmarked on high-concurrency HTTP parser: throughput increased by 26.4%!

We switched our game server clusters to mimalloc last year. Memory footprint stabilized and allocator lock contention vanished completely.

The huge page (THP) support in mimalloc also reduces TLB misses on large heap sizes.