Date: Fri, 31 Jan 2003 10:43:26 -0800 From: Peter Wemm <peter@wemm.org> To: Gary Thorpe <gathorpe79@yahoo.com> Cc: "Andrew R. Reiter" <arr@watson.org>, Julian Elischer <julian@elischer.org>, David Schultz <dschultz@uclink.berkeley.edu>, Terry Lambert <tlambert2@mindspring.com>, Scott Long <scott_long@btc.adaptec.com>, arch@FreeBSD.ORG Subject: Re: PAE (was Re: bus_dmamem_alloc_size()) Message-ID: <20030131184326.D70A42A89E@canning.wemm.org> In-Reply-To: <20030131181538.80926.qmail@web41206.mail.yahoo.com>
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Gary Thorpe wrote: > --- "Andrew R. Reiter" <arr@watson.org> wrote: > On Thu, 30 Jan 2003, > Julian Elischer wrote: > > > [...] > > :The reason for PAE is simple. > > : > > :Disk caches need not be in mapped memory. Physical memory will do. > > :If you want to cache more than 4GB, then PAE is an effective > > answer. > > : > > :(Assuming I have my TLAs the right way around..) > > : > > : > > > > Ya, well Im glad you brought that up, b/c aside from the anti-PAE > > rants > > that have been coming across (which are of ZERO USE -- THX FOR THAT), > > I > > do believe there are uses for it. I am glad to hear that someone is > > on > > it :) Thanks to them and those who organized the project for it. > > > > Cheers, > > Andrew > > > > -- > > Andrew R. Reiter > > arr@watson.org > > arr@FreeBSD.org > > Would this be part of a unified buffer-cache scheme though? If I have > been following correctly, this memory cannot be directly mapped into > processes address space (i.e. a process in one "segment" cannot access > directly memory in another "segment"), so how would it be useful as a > cache? Wouldn't this need lots of data copying as in bounce buffers? It the nasty PSE36 hack that cant be used for this. PAE works fine as cache since it is all available to all processes. Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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