From: ko1@... Date: 2018-08-10T09:33:13+00:00 Subject: [ruby-core:88433] [Ruby trunk Feature#13618] [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid Issue #13618 has been updated by ko1 (Koichi Sasada). We discussed about naming. ``` X IoThread.new{} X GreenThread.new{} X Thread::Green.new{} #124 ���most likely candidates���(vote: hsbt) X Thread.green{} #124 ���most likely candidates��� X Thread.create(scheduler: ���, args: ...) #124 ���most likely candidates��� Thread::Coop.new{} Thread::Cooperative.new{} # (usa) Thread::Nonpreemptive.new{} # (usa; these 2 names are very long, then they are good ^^) X NonpreemptiveThread.new {} # (mrkn) X NPThread.new {} # (mrkn) X Thread::Light (ko1) ``` X: rejected. Discussion is follow: * (1) At first, "green" is rejected because "green" is how to implement and there are several "green threads" can support preemption (such as Ruby 1.8). * (2) New toplevel name is rejected because is should be under `Thread` naming. * (3)`Thread.create` is rejected because it seems to make `Thread` class object and auto-fiber should be different class. * (4) Cooperative is rejected because it is also ambiguous. * (5) Nonpreemptive is considerable because it is different from what the application programmers (users) want. * (6) Thread::Light is rejected because this name does not make sense what the class is. So last devmeeting, we can't conclude the naming issue. BTW, I think this class should be "Thread" (I'm against (3), which by Matz). I think auto-fibers are Threads which have special attribute (scheduler). auto-fibers should have same methods in `Thread`. I'm not sure why Matz does not like this idea, though. There are several similar examples: * Proc (proc and lambda) * Fiber (semi-coroutine and coroutine (after `Fiber#transfer`) Weak examples: * Hash (compare_by_identity) * Struct (keyword_init) * Enumerator (support size or not) ---------------------------------------- Feature #13618: [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid https://bugs.ruby-lang.org/issues/13618#change-73488 * Author: normalperson (Eric Wong) * Status: Assigned * Priority: Normal * Assignee: normalperson (Eric Wong) * Target version: ---------------------------------------- ``` auto fiber schedule for rb_wait_for_single_fd and rb_waitpid Implement automatic Fiber yield and resume when running rb_wait_for_single_fd and rb_waitpid. The Ruby API changes for Fiber are named after existing Thread methods. main Ruby API: Fiber#start -> enable auto-scheduling and run Fiber until it automatically yields (due to EAGAIN/EWOULDBLOCK) The following behave like their Thread counterparts: Fiber.start - Fiber.new + Fiber#start (prelude.rb) Fiber#join - run internal scheduler until Fiber is terminated Fiber#value - ditto Fiber#run - like Fiber#start (prelude.rb) Right now, it takes over rb_wait_for_single_fd() and rb_waitpid() function if the running Fiber is auto-enabled (cont.c::rb_fiber_auto_sched_p) Changes to existing functions are minimal. New files (all new structs and relations should be documented): iom.h - internal API for the rest of RubyVM (incomplete?) iom_internal.h - internal header for iom_(select|epoll|kqueue).h iom_epoll.h - epoll-specific pieces iom_kqueue.h - kqueue-specific pieces iom_select.h - select-specific pieces iom_pingable_common.h - common code for iom_(epoll|kqueue).h iom_common.h - common footer for iom_(select|epoll|kqueue).h Changes to existing data structures: rb_thread_t.afrunq - list of fibers to auto-resume rb_vm_t.iom - Ruby I/O Manager (rb_iom_t) :) Besides rb_iom_t, all the new structs are stack-only and relies extensively on ccan/list for branch-less, O(1) insert/delete. As usual, understanding the data structures first should help you understand the code. Right now, I reuse some static functions in thread.c, so thread.c includes iom_(select|epoll|kqueue).h TODO: Hijack other blocking functions (IO.select, ...) I am using "double" for timeout since it is more convenient for arithmetic like parts of thread.c. Most platforms have good FP, I think. Also, all "blocking" functions (rb_iom_wait*) will have timeout support. ./configure gains a new --with-iom=(select|epoll|kqueue) switch libkqueue: libkqueue support is incomplete; corner cases are not handled well: 1) multiple fibers waiting on the same FD 2) waiting for both read and write events on the same FD Bugfixes to libkqueue may be necessary to support all corner cases. Supporting these corner cases for native kqueue was challenging, even. See comments on iom_kqueue.h and iom_epoll.h for nuances. Limitations Test script I used to download a file from my server: ----8<--- require 'net/http' require 'uri' require 'digest/sha1' require 'fiber' url = 'http://80x24.org/git-i-forgot-to-pack/objects/pack/pack-97b25a76c03b489d4cbbd85b12d0e1ad28717e55.idx' uri = URI(url) use_ssl = "https" == uri.scheme fibs = 10.times.map do Fiber.start do cur = Fiber.current.object_id # XXX getaddrinfo() and connect() are blocking # XXX resolv/replace + connect_nonblock Net::HTTP.start(uri.host, uri.port, use_ssl: use_ssl) do |http| req = Net::HTTP::Get.new(uri) http.request(req) do |res| dig = Digest::SHA1.new res.read_body do |buf| dig.update(buf) #warn "#{cur} #{buf.bytesize}\n" end warn "#{cur} #{dig.hexdigest}\n" end end warn "done\n" :done end end warn "joining #{Time.now}\n" fibs[-1].join(4) warn "joined #{Time.now}\n" all = fibs.dup warn "1 joined, wait for the rest\n" until fibs.empty? fibs.each(&:join) fibs.keep_if(&:alive?) warn fibs.inspect end p all.map(&:value) Fiber.new do puts 'HI' end.run.join ``` ---Files-------------------------------- 0001-auto-fiber-schedule-for-rb_wait_for_single_fd-and-rb.patch (82.8 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: