From: normalperson@... Date: 2014-03-30T03:28:29+00:00 Subject: [ruby-core:61760] [ruby-trunk - Feature #9632] [PATCH 0/2] speedup IO#close with linked-list from ccan Issue #9632 has been updated by Eric Wong. Eric Wong wrote: > normalperson@yhbt.net wrote: > > 0001-doubly-linked-list-from-ccan-to-manage-vm-living_thr.patch (68.1 KB) > > I'll de-duplicate the CC0 declaration files if allowed to commit this. > The original had symlinks, but I assume symlinks are not allowed in this > source tree for portability. Updated 0001 patch with deduplicated license files: http://bogomips.org/ruby.git/patch?id=b5401cdc6f72 I also renamed CCAN_INCLUDES to CCAN_LIST_INCLUDES in common.mk; in case we import other modules from ccan[1]. [1] - http://ccodearchive.net/ ---------------------------------------- Feature #9632: [PATCH 0/2] speedup IO#close with linked-list from ccan https://bugs.ruby-lang.org/issues/9632#change-45994 * Author: Eric Wong * Status: Open * Priority: Normal * Assignee: Koichi Sasada * Category: core * Target version: current: 2.2.0 ---------------------------------------- This imports the ccan linked-list (BSD-MIT licensed version of the Linux kernel linked list). I cut out some of the unused str* code (only for debugging), but it's still a big import of new code. Modifications to existing code is minimal, and it makes the living_threads iteration functions simpler. The improvement is great, and there may be future places where we could use a doubly linked list. = vm->living_threads: * before: st hash table had extra malloc overhead, and slow iteration due to bad cache locality * after: guaranteed O(1) insert/remove performance (branchless!) iteration is still O(n), but performance is improved in IO#close due to less pointer chasing = IO#close: further improvement with second linked list * before: IO#close is linear based on number of living threads * after: IO#close is linear based on number of waiting threads No extra malloc is needed (only 2 new pointers in existing structs) for a secondary linked-list for waiting FDs. I chose the ccan linked list over BSD for two reasons: 1) insertion and removal are both branchless 2) locality is improved if a struct may be a member of multiple lists git://80x24.org/ruby.git threads-list ---Files-------------------------------- 0002-speedup-IO-close-with-many-living-threads.patch (2.86 KB) 0001-doubly-linked-list-from-ccan-to-manage-vm-living_thr.patch (68.1 KB) -- https://bugs.ruby-lang.org/