FUSE File-Systems Pick Up Another Performance Boost With Symlink Caching

FUSE file-systems in user-space are set to be running faster with the upcoming Linux 4.20~5.0 kernel thanks to several performance optimizations.

The FUSE kernel code for this next Linux kernel cycle already has a hash table optimization and separately is copy file range support for efficient file copy operations. Staged today into the FUSE tree for the next cycle was yet another performance-boosting patch.

Facebook engineer Dan Schatzberg noted they are working on a FUSE file-system and they ended up discovering that symlink reads are not being cached in the page cache compared to file reads. When enabling the caching of symlinks, they at Facebook discovered around a 10% improvement to build times for source code being built from their FUSE file-system with the source tree being built having lots of symlinks.

Details on the symlink cache in this staged commit.