1) Increased innodb_write_io_thread from 4 to 16
2) Increased innodb_read_io_thread from 4 to 16
3) Altered innodb_flush_method=O_DIRECT

Sources:
http://dev.mysql.com/doc/innodb/1.1/en/innodb-performance-multiple_io_threads.htmlhttp://dev.mysql.com/doc/refman/5.5/en/optimizing-innodb-diskio.html