From owner-freebsd-performance@FreeBSD.ORG Wed Jun 25 19:26:50 2003 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 398DF37B401 for ; Wed, 25 Jun 2003 19:26:50 -0700 (PDT) Received: from stoneport.math.uic.edu (stoneport.math.uic.edu [131.193.178.160]) by mx1.FreeBSD.org (Postfix) with SMTP id 7263644005 for ; Wed, 25 Jun 2003 19:26:49 -0700 (PDT) (envelope-from djb-dsn-1056594442.62942@cr.yp.to) Received: (qmail 62943 invoked by uid 1017); 26 Jun 2003 02:27:22 -0000 Date: 26 Jun 2003 02:27:22 -0000 Message-ID: <20030626022722.62942.qmail@cr.yp.to> Automatic-Legal-Notices: See http://cr.yp.to/mailcopyright.html. From: "D. J. Bernstein" To: freebsd-performance@freebsd.org References: <009901c33b17$1a5090c0$10d4473e@PETEX31> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: Re: ten thousand small processes X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Jun 2003 02:26:50 -0000 I want separate processes for the memory protection. Each process is chrooted under its own uid, so it can't write to disk except through supplied file descriptors, and it can't hit other processes. (If I had a portable way to cut off other communication channels, such as creating new sockets, I'd do that too.) I'm willing to sacrifice one page per process for the sake of memory protection; I realize that it's hard to do better than that. But I'm not willing to casually piss away large fractions of a gigabyte of RAM. Not this decade, anyway. The lack of memory protection is exactly why I can't use threads. It's also why I'm not surprised to hear that processes are _slightly_ less efficient than threads. But something is seriously wrong if processes are _much_ less efficient than threads. ---D. J. Bernstein, Associate Professor, Department of Mathematics, Statistics, and Computer Science, University of Illinois at Chicago