Memory allocation performance remains critical for latency-sensitive applications. We benchmark the latest versions of mimalloc (2.2), jemalloc (5.4), and tcmalloc (4.6) across workload patterns representative of trading infrastructure.
Allocation-Heavy Workloads
For workloads dominated by small, frequent allocations (typical of FIX message parsing without PMR), mimalloc leads with 15% lower P99 latency than jemalloc and 22% lower than tcmalloc. mimalloc's segment-based free list provides excellent cache locality for rapid allocation/deallocation cycles.
Steady-State Workloads
For long-running applications with stable memory patterns (typical of pre-allocated trading systems), the differences narrow to within 3%. At this point, the choice matters less than ensuring allocations are off the hot path entirely.
Recommendation
For FIX engines: use PMR/arena allocation on the hot path and mimalloc as the global allocator for startup and cold-path operations. This combination provides the best of both worlds — zero hot-path allocation cost with efficient cold-path memory management.
