From owner-freebsd-stable Mon Apr 22 7:35:39 2002 Delivered-To: freebsd-stable@freebsd.org Received: from smtp.ixpres.com (smtp.ixpres.com [216.240.160.50]) by hub.freebsd.org (Postfix) with ESMTP id 5A72637B41F; Mon, 22 Apr 2002 07:35:33 -0700 (PDT) Received: from VIZION2000 (66-81-18-103-modem.o1.com [66.81.18.103]) by smtp.ixpres.com (8.9.3/8.9.3) with SMTP id HAA02964; Mon, 22 Apr 2002 07:32:40 -0700 (PDT) (envelope-from vizion@ixpres.com) Message-ID: <008001c1ea08$872b62d0$9865fea9@VIZION2000> From: " Vizion Communication" To: "David Schultz" , "Terry Lambert" Cc: , References: <20020421191440.J1721-100000@mail1.hub.org> <3CC3D494.649C2A8E@mindspring.com> <20020422060952.B31888@HAL9000.wox.org> Subject: Re: FreeBSD 4.5-STABLE not easily scalable to large servers ... ? Date: Mon, 22 Apr 2002 07:18:06 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Test - Please ignore ----- Original Message -----=20 From: "David Schultz" To: "Terry Lambert" Cc: ; Sent: Monday, April 22, 2002 6:09 AM Subject: Re: FreeBSD 4.5-STABLE not easily scalable to large servers ... = ? > Thus spake Terry Lambert : > > If you want more, then you need to use a 64 bit processor (or use a > > processor that supports bank selection, and hack up FreeBSD to do > > bank swapping on 2G at a time, just like Linux has been hacked up, > > and expect that it won't be very useful). >=20 > I'm guessing that this just means looking at more than 4 GB of memory > by working with 2 GB frames at a time. As I recall, David Greenman > said that this hack would essentially require a rewrite of the VM > system. Does this just boil down to using 36 bit physical addresses? > Are there plans for FreeBSD to support it, or is everyone just waiting > until 64 bit processors become more common? >=20 > > You can't > > really avoid that, for the most part, since there's a shared TLB > > cache that you really don't have opportunity to manage, other than > > by seperating 4M vs. 4K pages (and 2M, etc., for the Pentium Pro, > > though variable page granularity is not supported in FreeBSD, since > > it's not common to most hardware people actually have). >=20 > Does FreeBSD use 4M pages exclusively for kernel memory, as in > Solaris, or is there a more complicated scheme? >=20 > > If you increase the KVA, then you will decrease the UVA available to > > user processes. The total of the two can not exceed 4G. >=20 > In Linux, all of physical memory is mapped into the kernel's virtual > address space, and hence, until recently Linux was limited to ~3 GB of > physical memory. FreeBSD, as I understand, doesn't do that. So is > the cause of this limitation that the top half of the kernel has to > share a virtual address space with user processes? >=20 > I'll have to read those books one of these days when I have time(6). > Thanks for the info. >=20 > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-stable" in the body of the message >=20 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message