From owner-freebsd-hackers@FreeBSD.ORG Fri Oct 12 21:40:16 2007 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5F9AE16A419; Fri, 12 Oct 2007 21:40:16 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id 0667813C468; Fri, 12 Oct 2007 21:40:15 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from localhost (localhost [127.0.0.1]) by harmony.bsdimp.com (8.14.1/8.13.4) with ESMTP id l9CLdWwY007175; Fri, 12 Oct 2007 15:39:33 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Fri, 12 Oct 2007 15:39:32 -0600 (MDT) Message-Id: <20071012.153932.74743180.imp@bsdimp.com> To: kevin@your.org From: Warner Losh In-Reply-To: <2C263E0F-1231-4F73-A820-1A3265B72078@your.org> References: <20071012183534.bacd989b.vlady@gbservices.biz> <470F9BA9.5080606@FreeBSD.org> <2C263E0F-1231-4F73-A820-1A3265B72078@your.org> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0 (harmony.bsdimp.com [127.0.0.1]); Fri, 12 Oct 2007 15:39:33 -0600 (MDT) Cc: vlady@gbservices.biz, freebsd-hackers@FreeBSD.org, kris@FreeBSD.org, se@FreeBSD.org Subject: Re: Video memory as swap under FreeBSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Oct 2007 21:40:16 -0000 From: "Kevin - Your.Org" Subject: Re: Video memory as swap under FreeBSD Date: Fri, 12 Oct 2007 11:54:23 -0500 > > On Oct 12, 2007, at 11:07 AM, Stefan Esser wrote: > > > Vladimir Terziev schrieb: > >> You're right, > >> > >> the swap, typically configured, is much more than the amount of > >> the video memory, but in fact the swap is just a reserv, which > >> ensures continuation of the normal operations on the machine, at > >> times of peak loads. > >> In our days the amount of RAM placed in the servers is so much, > >> that the swap, in fact, is rarely used at all and a very small > >> amount of it (several MB) is used. In that cases having a very > >> fast swap space in the Video RAM, in addition to the disk swap, > >> would be a good solution. > > > > If you have a video card with so much excess memory, that you can > > use it > > for swap, then I wonder whether the video card has not been much too > > expensive ;-) > > > > How about spending $25 for another Gigabyte of RAM (real RAM, not > > SWAP) > > instead? > > > > I'm not commenting on if this is a good idea or not either way, but > at least one vendor of servers that we've been buying from is now > including 128 or 256MB of video ram(not UMA, real video ram) embedded > on the motherboard now. > > I thought it was odd too, until I asked our sales rep. The 8MB ATI > chipset they used to use would have disqualified them from being > "Vista Capable". > > So, whether we want it or not, we're getting at least 128MB of video > memory on our servers now. I'd thought about trying to use it for > something, but decided it wasn't worth the effort. :) It would be a cool hack. it would also be cool technology to have around because to 'swap' to the video ram, you need to have a way to map it to a device. And if you have that, then you have a short delta to many of the pci based battery backed ram disks. I'm sure that writing a small geom driver to cope wouldn't be very hard to do. Warner