I was reading through the Percona MySQL Server 5.5.30-30.2 release notes and noticed this gem:
Percona Server for MySQL will now be shipped with the libjemalloc library. Benchmark showing the impact of memory allocators on MySQL performance can be found in this blogpost. (Ignacio Nin)
The “Impact of memory allocators on MySQL performance” post is worth a read. Alternatives like lockless, jemalloc, and tcmalloc appear to provide better performance than traditional glibc.