Starting with InnoDB 1.1 with MySQL 5.5, concurrent access to the buffer pool is faster. Operations involving the flush list, a data structure related to the buffer pool, are now controlled by a separate mutex and do not block access to the buffer pool. You do not need to configure anything to take advantage of this speedup; it is fully automatic.
For more information about the InnoDB buffer pool, see
Section 7.9.1, “The InnoDB
Buffer Pool”.