Phoronix has published benchmarks comparing the performance of 'madvise' and 'always' modes for Transparent Hugepages (THP) on the Linux 6.18 LTS kernel. The tests address varying defaults across Linux distributions and respond to a reader request for modern data. Conducted on an AMD EPYC server running Ubuntu, the review highlights configuration options for THP without altering hardware or software.
Transparent Hugepages (THP) are a Linux kernel feature designed to improve memory management by using larger page sizes, potentially boosting performance. However, distributions differ in their default settings: Fedora Workstation and Ubuntu opt for the 'madvise' mode, where applications must explicitly request huge pages, while CachyOS and openSUSE use 'always', applying huge pages by default.
A Phoronix Premium supporter prompted these benchmarks to evaluate the impact of these modes on contemporary workloads. The tests were performed on an Ubuntu 26.04 development snapshot equipped with the Linux 6.18 LTS kernel, running on a single-socket Supermicro server powered by an AMD EPYC 9655P processor.
To switch modes, users can write 'always' or 'madvise' to the sysfs file at /sys/kernel/mm/transparent_hugepage/enabled, or set the boot parameter transparent_hugepages=always. For the benchmarks, the only change was rebooting into the alternative THP configuration, ensuring a controlled comparison.
This review provides fresh reference data for Linux server administrators considering THP defaults, covering a variety of workloads to inform decisions on performance tuning in modern environments.