From owner-freebsd-arm@freebsd.org Wed Aug 15 22:54:51 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 EB32E107366D for ; Wed, 15 Aug 2018 22:54:50 +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 54A4481653; Wed, 15 Aug 2018 22:54:50 +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 w7FMt5rg059283 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 15 Aug 2018 15:55:06 -0700 (PDT) (envelope-from fbsd@www.zefox.net) Received: (from fbsd@localhost) by www.zefox.net (8.15.2/8.15.2/Submit) id w7FMt40i059282; Wed, 15 Aug 2018 15:55:05 -0700 (PDT) (envelope-from fbsd) Date: Wed, 15 Aug 2018 15:55:04 -0700 From: bob prohaska To: Warner Losh Cc: Mark Millard , freebsd-arm , Mark Johnston , bob prohaska Subject: Re: RPI3 swap experiments (grace under pressure) Message-ID: <20180815225504.GB59074@www.zefox.net> References: <20180813021226.GA46750@www.zefox.net> <0D8B9A29-DD95-4FA3-8F7D-4B85A3BB54D7@yahoo.com> <20180813185350.GA47132@www.zefox.net> <20180814014226.GA50013@www.zefox.net> <20180815013612.GB51051@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: Wed, 15 Aug 2018 22:54:51 -0000 On Tue, Aug 14, 2018 at 10:26:39PM -0600, Warner Losh wrote: [eloquent VM discussion snipped] > So I think what's well tuned for the gear that's in a server doing > traditional database and/or compute workloads may not be so well tuned for > the RPi3 when you put NAND that can vary a lot in performance, as well as > have fast reads and slow writes when the mix isn't that high. The system > can be tuned to cope, but isn't tuned that way out of the box. > > tl;dr: these systems are enough different than the normal system that > additional tuning is needed where the normal systems work great out of the > box. Plus some code tuneups may help the algorithms be more dynamic than > they are today. > When I started this goose chase, after zero problems with RPI2, I thought the issue was arm64-related and might be of some fundamental importance. Thanks to many people I now understand it's a confluence of USB and flash memory artifacts, made evident by the demands of clang6. Elsewhere I noted that I'm seeking "the robustness of a Mars rover, using a rack server OS on a cellphone motherboard". 8-) With my thanks to all for much patient good counsel, bob prohaska