Glibc 2.35 Bringing Improved Huge Pages Handling, New Tunable

Written by Michael Larabel in GNU on 15 December 2021 at 07:33 PM EST. Add A Comment
Glibc 2.35 is introducing the new tunable glibc.malloc.hugetlb that can help with improving system performance for some workloads making use of this tunable, depending upon your kernel's hugepages configuration.

The GNU C Library has landed huge pages support on Linux for mmap and arenas code that can be enabled with a new glibc tunable. That same tunable also allows enabling madvise support for transparent huge pages (THP).

The code merged this afternoon to Glibc Git across multiple commits explains:
On Linux, a new tunable, glibc.malloc.hugetlb, can be used to either make malloc issue madvise plus MADV_HUGEPAGE on mmap and sbrk or to use huge pages directly with mmap calls with the MAP_HUGETLB flags). The former can improve performance when Transparent Huge Pages is set to 'madvise' mode while the latter uses the system reserved huge pages.

This madvise/THP work for Glibc was written by Linaro's Adhemerval Zanella. More details for those interested in these latest commits.

This better handling of Linux THP will be found in Glibc 2.35 due out in February along with plenty of other improvements to this common Linux C library implementation.
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