Date: Mon, 5 May 2003 13:08:01 -0500 From: "Kyle Rollin" <knr@xy.hartford.edu> To: freebsd-performance@freebsd.org Subject: Re: Real and availible RAM Message-ID: <20030505180224.M13866@xy.hartford.edu> In-Reply-To: <3801.172.182.185.39.1052141430.squirrel@bluhayz.homeunix.org> References: <3801.172.182.185.39.1052141430.squirrel@bluhayz.homeunix.org>
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On Mon, 5 May 2003 09:30:30 -0400 (EDT), agent dero wrote > I have been looking through the kernel boot messages in /var/log > while working on some custom kernel compile work, and I came across something > that I think is very interesting, but doesn't make sense. > real memory = 100663296 (98304K bytes) > avail memory = 94580736 (92364K bytes) > > This tells me that FreeBSD recognizes my 98MB of RAM, but it only > uses 92MB? Are the 6MB of RAM that are left getting shafted, and > just using power, but not being addressed by FreeBSD? Does this slow > down my machine at all, I mean, is there a percentage to this? Where > only x% of 100% RAM is availible or usable? > <snip> If you look at the way x86 architecture is designed (and somebody else can feel free to correct me if I'm wrong), but system memory is often used in the caching/shadowing of BIOS. This is where a lot of system memory often goes before the OS is loaded - also, as Rob said, the kernel itself will take up memory before the rest of the OS is booted. If you're concerned that you might run out of memory, RAM is cheap - adding a stick of 128MB will greatly reduce that risk :) -Kyle Rollin
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