From owner-freebsd-arm@freebsd.org Tue Aug 14 01:42:17 2018 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DD08510607BD for ; Tue, 14 Aug 2018 01:42:17 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (www.zefox.net [50.1.20.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "www.zefox.org", Issuer "www.zefox.org" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 3D3F8772EA; Tue, 14 Aug 2018 01:42:16 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (localhost [127.0.0.1]) by www.zefox.net (8.15.2/8.15.2) with ESMTPS id w7E1gRWb050986 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 13 Aug 2018 18:42:27 -0700 (PDT) (envelope-from fbsd@www.zefox.net) Received: (from fbsd@localhost) by www.zefox.net (8.15.2/8.15.2/Submit) id w7E1gQG7050985; Mon, 13 Aug 2018 18:42:26 -0700 (PDT) (envelope-from fbsd) Date: Mon, 13 Aug 2018 18:42:26 -0700 From: bob prohaska To: Mark Millard Cc: Mark Johnston , John Kennedy , freebsd-arm , bob prohaska Subject: Re: RPI3 swap experiments (grace under pressure) Message-ID: <20180814014226.GA50013@www.zefox.net> References: <20180809033735.GJ30738@phouka1.phouka.net> <20180809175802.GA32974@www.zefox.net> <20180812173248.GA81324@phouka1.phouka.net> <20180812224021.GA46372@www.zefox.net> <20180813021226.GA46750@www.zefox.net> <0D8B9A29-DD95-4FA3-8F7D-4B85A3BB54D7@yahoo.com> <20180813185350.GA47132@www.zefox.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Aug 2018 01:42:18 -0000 [Altered subject, philosophical question] On Mon, Aug 13, 2018 at 01:05:38PM -0700, Mark Millard wrote: > > Here there is architecture choice and goals/primary > contexts. FreeBSD is never likely to primarily target > anything with a workload like buildworld buildkernel > on hardware like rpi3's and rpi2 V1.1's and > Pine64+ 2GB's and so on. > I understand that the RPi isn't a primary platform for FreeBSD. But, decent performance under overload seems like a universal problem that's always worth solving, whether for a computer or an office. The exact goals might vary, but coping with too much to do and not enough to do it with is humanity's oldest puzzle. Maybe I should ask what the goals of the OOMA process serve. I always thought an OS's goals were along the lines of: 1. maintain control 2. get the work done 3. remain responsive There's at least some degree of conflict between all of them, made worse when the workload grows beyond the design assumptions. The RPI makes the issue more visible, but it's always lurking. OOMA seems to sacrifice getting work done, potentially entirely, in support of keeping the system responsive and under control. To have some fun with the office analogy, when business is slow the clerk serves customers as they come in. When things get busy, the clerk says "take a number". When they get really busy new customers are told "come back tomorrow" and when they get absolutely frantic present customers are told "I can't finish this now, I'll call you when it's done". That's grace under pressure. What do FreeBSD's designers want the system to do as it's progressively overworked? Is the office analogy too ambitious? Thanks for reading, and apologies for the ruminating. bob prohaska