From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-3.4 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id 776A11F424 for ; Thu, 26 Apr 2018 04:57:21 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 99DF8120900; Thu, 26 Apr 2018 13:57:17 +0900 (JST) Received: from o1678948x4.outbound-mail.sendgrid.net (o1678948x4.outbound-mail.sendgrid.net [167.89.48.4]) by neon.ruby-lang.org (Postfix) with ESMTPS id 9606E120884 for ; Thu, 26 Apr 2018 13:57:14 +0900 (JST) Received: by filter0023p3las1.sendgrid.net with SMTP id filter0023p3las1-22461-5AE15C27-D 2018-04-26 04:57:11.275297161 +0000 UTC Received: from herokuapp.com (ec2-54-204-100-110.compute-1.amazonaws.com [54.204.100.110]) by ismtpd0025p1mdw1.sendgrid.net (SG) with ESMTP id FnriSZY8R7uD6HuSM-zTGQ Thu, 26 Apr 2018 04:57:10.987 +0000 (UTC) Date: Thu, 26 Apr 2018 04:57:11 +0000 (UTC) From: samuel@oriontransfer.org To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 62035 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 13618 X-Redmine-Issue-Author: normalperson X-Redmine-Issue-Assignee: normalperson X-Redmine-Sender: ioquatix X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: ync6xU2WACa70kv/Ymy4QrNMhiuLXJG8OTL2vJD1yS7LLgFkqSpypzHJL4eG0awbJtGot53IAzbkS4 5PyUT6+gp9zu4jxnxK2MfRAfWL+YBfAWYKKmSN2BNIBYVtfaVAQDiNEuhsGfWr44u8LLU5fALI8HVp +YBeSHll3MR8Ck1XeOotJ790lmqWh3LS9i/26Fe1nMkWIExPlwyqn3WK/g== X-ML-Name: ruby-core X-Mail-Count: 86689 Subject: [ruby-core:86689] [Ruby trunk Feature#13618] [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #13618 has been updated by ioquatix (Samuel Williams). If you are unsure of a good definition for the reactor pattern, I think this is a good one: https://en.wikipedia.org/wiki/Reactor_pattern except the assumption that you need to invert flow control which is not necessary using fibers. In my experience, experimenting with implementations that use shared epoll/kqueue on a background thread, the thread contention is a pretty big overhead, I think somewhere between 5x and 10x overhead but I'd prefer to back that up with real numbers. Not only that, the practical implementation is more complicated since you need to implement IPC, locking etc. It's simpler to have a per-thread reactor, and the practical realities of Ruby as it stands with the GVL mean that using more than one thread is a terrible idea if you actually care about throughput/performance. I'm writing up a summary of this but it's not finished yet, it will include actual numbers to back up the above assertions, once I'm done I will post it here. ---------------------------------------- Feature #13618: [PATCH] auto fiber schedule for rb_wait_for_single_fd and rb_waitpid https://bugs.ruby-lang.org/issues/13618#change-71649 * 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/