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=-3.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,SPF_PASS, T_DKIM_INVALID 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 4F62F1F667 for ; Wed, 16 Aug 2017 17:20:01 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id AA11212082D; Thu, 17 Aug 2017 02:19:57 +0900 (JST) Received: from o1678916x28.outbound-mail.sendgrid.net (o1678916x28.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 00EBC120817 for ; Thu, 17 Aug 2017 02:19:55 +0900 (JST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=sendgrid.me; h=from:to:references:subject:mime-version:content-type:content-transfer-encoding:list-id; s=smtpapi; bh=4PXshHyNq/Ich71a3E2S7D4aJwI=; b=W/2tltUmSSM9mHDuXm kDoHUEr+VIaZn0Xc1QzPkq7Zk2Z3Ey5/wDQ/Ib7mo0TMVrjp2dxwgZEMiWDIFN6Y 3I04FyYAthLXWOsKWR48DWMmmsRewN7+WZm5wrXge7aAGhEC1P0xxkonDnKshXLz MoiRDE6Zb3fzNwW+E8xHPm+7w= Received: by filter0008p3mdw1.sendgrid.net with SMTP id filter0008p3mdw1-14623-59947EB6-11 2017-08-16 17:19:50.297632172 +0000 UTC Received: from herokuapp.com (ec2-54-161-242-237.compute-1.amazonaws.com [54.161.242.237]) by ismtpd0039p1mdw1.sendgrid.net (SG) with ESMTP id hPYFmLtpTS6JCQOyQLS7VA for ; Wed, 16 Aug 2017 17:19:50.232 +0000 (UTC) Date: Wed, 16 Aug 2017 17:19:50 +0000 (UTC) From: git@chuckremes.com To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 57453 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 13821 X-Redmine-Issue-Author: cremes X-Redmine-Sender: cremes 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/Ymy4QrNMhiuLXJG8OTL2vJD1yS7s8/mkR6mTPPt1i0ef+JYBtNmR+tIkt3qbzq 9hygwPDf2HwAS1XqHsfQQ+uc32xsf4RzMTy7jfnf7NjBhvhUA93OfNsmP4o3Jy+mwguVQNi6ZKdGEw G5QdVoaCeJnIAuKFMIvEwi41hB2KNgVzmDSrx9Yfj5pUyubOD4NLXpYpDQ== X-ML-Name: ruby-core X-Mail-Count: 82402 Subject: [ruby-core:82402] [Ruby trunk Feature#13821] Allow fibers to be resumed across threads 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 #13821 has been reported by cremes (Chuck Remes). ---------------------------------------- Feature #13821: Allow fibers to be resumed across threads https://bugs.ruby-lang.org/issues/13821 * Author: cremes (Chuck Remes) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Given a Fiber created in ThreadA, Ruby 2.4.1 (and earlier releases) raise a FiberError if the fiber is resumed in ThreadB or any other thread other than the one that created the original Fiber. Sample code attached to demonstrate problem. If Fibers are truly encapsulating all of the data for the continuation, we should be allowed to move them between Threads and resume their operation. Why? One use-case is to support the async-await asynchronous programming model. In that model, a method marked async runs *synchronously* until the #await method is encountered. At that point the method is suspended and control is returned to the caller. When the #await method completes (asynchronously) then it may resume the suspended method and continue. The only way to capture this program state, suspend and resume, is via a Fiber. example: ``` class Wait include AsyncAwait def dofirst async do puts 'Synchronously print dofirst.' result = await { dosecond } puts 'dosecond is complete' result end end def dosecond async do puts 'Synchronously print dosecond from async task.' slept = await { sleep 3 } puts 'Sleep complete' slept end end def run task = dofirst puts 'Received task' p AsyncAwait::Task.await(task) end end Wait.new.run ``` ``` # Expected output: # Synchronous print dofirst. # Received task # Synchronously print dosecond from async task. # Sleep complete # dosecond is complete # 3 ``` Right now the best way to accomplish suspension of the #dofirst and #dosecond commands and allow them to run asynchronously is by passing those blocks to *another thread* (other than the callers thread) so they can be encapsulated in a new Fiber and then yielded. When it's time to resume after #await completes, that other thread must lookup the fiber and resume it. This is lots of extra code and logic to make sure that fibers are only resumed on the threads that created them. Allowing Fibers to migrate between threads would eliminate this problem. ---Files-------------------------------- fiber_across_threads.rb (377 Bytes) wait.rb (728 Bytes) -- https://bugs.ruby-lang.org/