Date: Wed, 24 Apr 2002 09:16:53 +0300 From: Vallo Kallaste <kalts@estpak.ee> To: "Marc G. Fournier" <scrappy@hub.org>, Terry Lambert <tlambert2@mindspring.com>, freebsd-current@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.5-STABLE not easily scalable to large servers ... ? Message-ID: <20020424061653.GA33245@myhakas.estpak.ee> In-Reply-To: <20020423214011.B3593@HAL9000.wox.org> References: <3CC4C683.F9AEF14E@mindspring.com> <20020423092909.N1721-100000@mail1.hub.org> <20020423184534.GA30212@myhakas.estpak.ee> <20020423214011.B3593@HAL9000.wox.org>
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On Tue, Apr 23, 2002 at 09:40:11PM -0700, David Schultz <dschultz@uclink.Berkeley.EDU> wrote: > > Userspace processes will allocate memory from UVA space and can > > grow over 1GB of size if needed by swapping. You can certainly > > have more than one over-1GB process going on at the same time, > > but swapping will constrain your performance. > > It isn't a performance constraint. 32-bit architectures have > 32-bit pointers, so in the absence of segmentation tricks, a > virtual address space can only contain 2^32 = 4G locations. If > the kernel gets 3 GB of that, the maximum amount of memory that > any individual user process can use is 1 GB. If you had, say, 4 > GB of physical memory, a single user process could not use it all. > Swap increases the total amount of memory that *all* processes can > allocate by pushing some of the pages out of RAM and onto the > disk, but it doesn't increase the total amount of memory that a > single process can address. Thank you, Terry and David, now I grasp how it should work (I hope). I really miss some education, but that's life. -- Vallo Kallaste kalts@estpak.ee To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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