title: Log the kernel splitting huge pages into normal sized pages
name: hugepage_split.stp
version: 1.0
author: William Cohen
keywords: memory
subsystem: memory
status: production
exit: user-controlled
output: sorted-list
scope: system-wide
description: Because some portions of the kernel code only work with normal-sized pages the kernel may convert a huge page into a set of normal-sized pages using a split operation. This operation may be relatively expensive and noticeable to latency sensitive programs. You can identify if split operations are occurring with the systemtap hugepage_split.stp script.
test_support: stap -l 'kernel.function("split_huge_page")'
test_check: stap -p4 hugepage_split.stp
test_installcheck: stap hugepage_split.stp -T 1