From: sam.saffron@... Date: 2018-02-02T05:46:33+00:00 Subject: [ruby-core:85335] [Ruby trunk Feature#13618] [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid Issue #13618 has been updated by sam.saffron (Sam Saffron). Having discussed this with Koichi I think he is wanting to merge this into core but the big blocker here is naming and some small details. Koichi is not particularly fond of `Thread.current << lambda {}` cause he feels it is a bit confusing. Especially since we have Thread.current["x"]. I think this works (albeit with some multithreading concerns): ``` Thread.current.scheduler << lambda {} Thread.current.scheduler.resume Thread.current.scheduler.current Thread.current.scheduler.current&.yield ``` > One question, is how will Thread#[]/#[]= be handled inside the lambda? I think it should be simply treated as a Thread global so it is shared between the lambdas. If you need lambda specific storage we could implement something else. Otherwise it complicates stuff. Regarding: > Simply making a per-thread reactor and making read/write calls non-blocking only solves about 10% of the problem IMHO. I am not sure if I agree with this. This change will give us a single threaded reactor and allow us to continue using the exact same API we use elsewhere. It drops in to existing Ruby code much cleaner than introducing new APIs, File#read yields, PG::Connection#exec yields and so on. This is something we have wanted for your years. We basically get EventMachine without needing to adhere to the EventMachine API. It would be a great first step. One big question I have though is how rb_thread_call_with_gvl and rb_thread_call_without_gvl will be handled, cause without magic handling there we don't get free PG / MiniRacer support and many others which is a huge shame. ---------------------------------------- Feature #13618: [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid https://bugs.ruby-lang.org/issues/13618#change-70120 * 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: