Date: Tue, 23 Apr 2002 23:04:49 +0300 From: Vallo Kallaste <kalts@estpak.ee> To: Terry Lambert <tlambert2@mindspring.com> Cc: kalts@estpak.ee, "Marc G. Fournier" <scrappy@hub.org>, freebsd-current@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.5-STABLE not easily scalable to large servers ... ? Message-ID: <20020423200449.GA30662@myhakas.estpak.ee> In-Reply-To: <3CC5B52B.49A5A719@mindspring.com> References: <3CC4C683.F9AEF14E@mindspring.com> <20020423092909.N1721-100000@mail1.hub.org> <20020423184534.GA30212@myhakas.estpak.ee> <3CC5B52B.49A5A719@mindspring.com>
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On Tue, Apr 23, 2002 at 12:25:31PM -0700, Terry Lambert <tlambert2@mindspring.com> wrote: > Vallo Kallaste wrote: > > You can have up to ~12GB of usable swap space, as I've heard. Don't > > remember why such arbitrary limit, unfortunately. Information about > > such topics is spread over several lists arhives, usually the > > subjects are strange, too.. so hard to find out. As I understand it > > you are on the track, having 3GB allocated to KVA means 1GB for UVA, > > whatever it exactly means. 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. > > I'm sure Terry or some other knowledgeable person will correct me if > > it doesn't make sense. > > Actually, you have a total concurrent virtual address space of 4G. > > If you assign 3G of that to KVA, then you can never exceed 1G of > space for a user process, under any circumstances. > > This is because a given user process and kernel must be able > to exist simultaneously in order to do things like copyin/copyout. Hmm, ok, but can we have more than one 1G user process at one time? Four 500MB ones and so on? Somehow I've made such conclusion based on previous information. Should be so, otherwise I don't understand how swapping will fit into overall picture. -- Vallo Kallaste kalts@estpak.ee To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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