Issue #2375 has been updated by Johannes Hofmann.
Both, the hash based version and my initial tree based one have an issue with renames onto an existing file (e.g. touch a; touch b; mv b a; rm b). A fixed tree based version is available at http://leaf.dragonflybsd.org/~hofmann/tmpfs_rbtree1.diff This version also gets rid of the TAILQ and maintains directory entries only in the rb-tree. I did some performance tests on real hardware with a minimal C-program (http://leaf.dragonflybsd.org/~hofmann/file_create.c) with following results: tmpfs as in master (4018c6eddd): hofmann@blob:/mnt/bla >time file_create 50000 real 1m16.594s user 0m0.617s sys 1m14.681s tmpfs as in master (ae879fe6cd + tmpfs5.diff + compile fixes): hofmann@blob:/mnt/bla >time /home/hofmann/test/file_create 50000 real 0m5.706s user 0m0.359s sys 0m5.211s tmpfs_rb no tailq (4018c6eddd + tmpfs_rbtree1.diff): hofmann@blob:/mnt/bla >time /home/hofmann/test/file_create 50000 real 0m3.396s user 0m0.195s sys 0m3.203s ---------------------------------------- Bug #2375: Wishlist: tmpfs directory lookup optimization http://bugs.dragonflybsd.org/issues/2375 Author: Venkatesh Srinivas Status: New Priority: Normal Assignee: Category: Target version: tmpfs directories are structured as lists of directory entries; this leads to linear lookup costs. Directories with many files become fairly expensive to operate on. http://leaf.dragonflybsd.org/~vsrinivas/tmpfs5.diff is a patch that introduces a 64-wide hash table (of lists) to speed up lookups. The patch is currently littered with debugging cruft and could benefit from cleaning. http://leaf.dragonflybsd.org/~hofmann/tmpfs_rbtree.diff is a cleaner patch that uses an RB-tree, keyed on the name of the file in question. Both approaches are solid improvements over the current lists, but could use some testing (benchmarking) to determine which is worth applying. The hash list patch has had many hours of fsstress testing; it now works well. The tree patches at the same points. -- You have received this notification because you have either subscribed to it, or are involved in it. To change your notification preferences, please click here: http://bugs.dragonflybsd.org/my/account
