Changing Default Memory Allocator to tcmalloc


Starting in 389-ds-base-1.3.6 (and RHEL 7.4) the Directory Server will be using tcmalloc as its default memory allocator. The benefits of using tcmalloc are a significant smaller virtual memory size & growth, and a slight performance increase. Due to the way the Directory Server is using memory internally the standard glibc allocator created a much larger memory footprint. This caused issues like the server’s memory footprint not matching the cache settings, and ultimately running out of memory (OOM).

Major configuration options and enablement

There is no server configuration. This is enabled at compile time by using the configure option “–enable-tcmalloc”.


gperftools-libs package on RHEL/Fedora contains the tcmalloc libraries, and are needed to run Directory Server.

External Impact

Building the server on platforms other than RHEL and Fedora would need to have some form of tcmalloc (libtcmalloc) available on that system.



Last modified on 1 March 2017