Beyond malloc

Did you know that malloc isn't the only way to allocate memory? In fact, it's just a convenient wrapper hiding a complex world of system calls and optimizations that power your applications.

The actual memory allocation happens through system calls like brk, sbrk, and mmap. malloc is just a convenient wrapper that makes these complex operations simple for developers to use.

Most Linux systems use glibc's ptmalloc2 as the standard malloc implementation. While it works for general purposes, it has limitations like lock contention, memory fragmentation, and poor cache locality that become bottlenecks in production systems.

Use jemalloc when you have long-running processes where fragmentation accumulates, need consistent performance, prefer memory efficiency, and want detailed statistics. Popular packages like Redis and Varnish have switched to jemalloc for improved performance.

Use tcmalloc when you have many threads with heavy allocation activity, lots of small short-lived allocations, and prefer maximum throughput over memory usage. Cloudflare switched to tcmalloc and saw a 2.5 times decrease in memory usage.

Now you know that malloc is just the tip of the iceberg. Whether you choose jemalloc for memory efficiency or tcmalloc for speed, understanding these alternatives can dramatically improve your application's performance. Which one will you try first?