From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Concurrency, again Date: Fri, 14 Oct 2016 17:48:08 -0400 Message-ID: References: <87wq97i78i.fsf@earlgrey.lan> <86k2dk77w6.fsf@molnjunk.nocrew.org> <9D64B8EA-DB52-413D-AE6A-264416C391F3@iotcl.com> <83int1g0s5.fsf@gnu.org> <83twckekqq.fsf@gnu.org> <83mvi9a3mh.fsf@gnu.org> <20161012165911.58437154@jabberwock.cb.piermont.com> <20161012173314.799d1dc5@jabberwock.cb.piermont.com> <8360owaj2s.fsf@gnu.org> <20161013092701.77461800@jabberwock.cb.piermont.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1476494175 1959 195.159.176.226 (15 Oct 2016 01:16:15 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 15 Oct 2016 01:16:15 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Richard Stallman Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Oct 15 03:16:11 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bvDZt-0006fO-2c for ged-emacs-devel@m.gmane.org; Sat, 15 Oct 2016 03:15:57 +0200 Original-Received: from localhost ([::1]:50082 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bvDZq-0000yL-Vq for ged-emacs-devel@m.gmane.org; Fri, 14 Oct 2016 21:15:55 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:54336) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bvDZZ-0000rj-Rt for emacs-devel@gnu.org; Fri, 14 Oct 2016 21:15:38 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bvDZY-0005Pv-3k for emacs-devel@gnu.org; Fri, 14 Oct 2016 21:15:37 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.181]:42490) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1bvDZW-0004zG-9g; Fri, 14 Oct 2016 21:15:36 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0BHAgALW9BX/8Hk92hdGwEBAQMBAQFBgmwBAQEBAR6ETYVQhGWrEYIDhhYEAgKBaTkUAQIBAQEBAQEBXieEYgEBAwFWIwULCw4mEhQYDSSIVQi8VQEBAQcCJYp9ihwBBJlZkRWHeIYLkEseNoRsIIYKAQEB X-IPAS-Result: A0BHAgALW9BX/8Hk92hdGwEBAQMBAQFBgmwBAQEBAR6ETYVQhGWrEYIDhhYEAgKBaTkUAQIBAQEBAQEBXieEYgEBAwFWIwULCw4mEhQYDSSIVQi8VQEBAQcCJYp9ihwBBJlZkRWHeIYLkEseNoRsIIYKAQEB X-IronPort-AV: E=Sophos;i="5.30,296,1470715200"; d="scan'208";a="275886409" Original-Received: from 104-247-228-193.cpe.teksavvy.com (HELO pastel.home) ([104.247.228.193]) by smtp.teksavvy.com with ESMTP; 14 Oct 2016 21:14:52 -0400 Original-Received: by pastel.home (Postfix, from userid 20848) id 277B26507A; Fri, 14 Oct 2016 17:48:08 -0400 (EDT) In-Reply-To: (Richard Stallman's message of "Fri, 14 Oct 2016 17:01:24 -0400") X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 206.248.154.181 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:208264 Archived-At: > I thought that "concurrency" and "parallelism" were the same. They're related and they overlap. If you use use a pseudo-parallel system (such as the `concurrency` branch), then you have concurrency but not parallelism. Vector processing (or GPUs nowadays) on the other hand, offers parallelism but not concurrency. To take another example, from the world of memory management: - A concurrent GC is one where the mutator is not stopped while the collector does its job. - A parallel GC is one where the collector divides its job into chunks that can be performed at the same time by different CPUs. It may be concurrent or not. Stefan