From owner-freebsd-arch Tue Oct 8 12:10:40 2002 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 313F137B401 for ; Tue, 8 Oct 2002 12:10:39 -0700 (PDT) Received: from rootlabs.com (root.org [67.118.192.226]) by mx1.FreeBSD.org (Postfix) with SMTP id CB02D43E6A for ; Tue, 8 Oct 2002 12:10:38 -0700 (PDT) (envelope-from nate@rootlabs.com) Received: (qmail 11470 invoked by uid 1000); 8 Oct 2002 19:10:39 -0000 Date: Tue, 8 Oct 2002 12:10:39 -0700 (PDT) From: Nate Lawson To: "Vladimir B. Grebenschikov" Cc: arch@FreeBSD.org Subject: Re: using mem above 4Gb was: swapon some regular file In-Reply-To: <1034094238.899.14.camel@vbook.express.ru> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=X-UNKNOWN Content-Transfer-Encoding: 8BIT Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 8 Oct 2002, Vladimir B. Grebenschikov wrote: > χ Tue, 08.10.2002, Χ 19:50, Mikhail Teterin ΞΑΠΙΣΑΜ: > > On Tuesday 08 October 2002 11:41 am, Terry Lambert wrote: > > = Terry Lambert wrote: > > = > So whatever connections you are getting now... halve that, or less, > > = > to get a window for your RAM disk (you will need KVA for mappings > > = > for all the memory that *can* be in the window, etc.). > > = > > = To emphasize this: if you are using 4K pages, you will need: > > = > > = 4K/1M * 64G = 256M > > = > > = ...1/4 of 1G of memory outside the window, just for page tables. > > = > > = Also, if we still were using an mbuf per connection for the > > = template, for 1,000,000 connections, that's 256M of RAM -- another > > = 1/4 gig. > > > > = Yeah, most people don't think in these terms; personally, I like > > = to call it "Extreme BSD". 8-). > > > > Although this is fascinating read -- it getting further and further away > > from the original subject. And from the modified one too -- I don't > > believe Vladimir said anything about networking... > > Exactly, Terry is right about large number of relative-small > network-access processes (say apaches). But there are some other cases, > say you have some DB server with huge index, say 10Gb, I think keep > index in RAM effective than on disk. It's often surprisingly effective to just access the index on disk and tune your VM cache instead. You can lose performance by double-caching data. -Nate You teach a child to read and he or her will be able to pass a literacy test. -- President Bush, 2/21/2001 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message