Date: Mon, 3 Apr 2006 14:37:38 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Mike Jakubik <mikej@rogers.com> Cc: freebsd-amd64@freebsd.org Subject: Re: Status of NX bit support. Message-ID: <20060403213738.GA99346@troutmask.apl.washington.edu> In-Reply-To: <44319241.7080208@rogers.com> References: <44301C6D.3010206@rogers.com> <200604031442.43477.jhb@freebsd.org> <44318E3F.6080808@rogers.com> <20060403211943.GA99241@troutmask.apl.washington.edu> <44319241.7080208@rogers.com>
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On Mon, Apr 03, 2006 at 05:23:13PM -0400, Mike Jakubik wrote: > Steve Kargl wrote: > >On Mon, Apr 03, 2006 at 05:06:07PM -0400, Mike Jakubik wrote: > > > >>John Baldwin wrote: > >> > >>>On Sunday 02 April 2006 14:48, Mike Jakubik wrote: > >>> > >>>>I was wondering what the status of the NX bit support is. Is the pmap.c > >>>>code still broken or is support enabled and functioning by default? > >>>> > >>>I don't think the status has changed. > >>> > >>Well that sucks.. I guess then there really is no reason for someone to > >>run in amd64 mode unless you need more than 4GB of ram. > >> > > > >You're joking, right? How many registers are available for the > >i386? How many registers are available to an AMD64 cpu in > >64-bit mode? > > > > Yes, but doesn't the software have to be written to take advantage of > these? (What about Intels 64bit extensions, do they have the same extra > registers as the amd cpus?). As far as i can see so far, amd64 mode just > eats more memory. Do you do a large amount of number crunching? AMD paid for work on GCC to optimize gcc's machine description. I've never tried a benchmark of FreeBSD i386 versus FreeBSD amd64 for number crunching. It would be interesting to see a comparison of math/atlas on amd64 hardware under FreeBSD i386 and amd64. Someday, if I have time .... The livermore loops may also be interesting. -- Steve
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