56267http://bugs.mysql.com/bug.php?id=56267ClosedServer: Packagingtcmalloc lib (libtcmalloc_minimal.so) is missing from mysql 5.5 binaryAs per http://dev.mysql.com/doc/refman/5.5/en/mysqld-safe.html#option_mysqld_safe_malloc-lib: "Linux users can use the libtcmalloc_minimal.so included in binary packages by adding these lines to the my.cnf file" However, libtcmalloc is absent from MySQL 5.5 binaries. libtcmalloc can give 2x performance on some workloads (readonly). For example: sysbench readonly test, 64 threads: 1760.08 per sec. with tcmalloc vs 725.44 per sec. without tcmalloc1403766128276250313805578615.5LinuxAnyS3 (Non-critical)