Date: Wed, 18 May 2005 22:46:30 -0700 From: "David O'Brien" <obrien@freebsd.org> To: =?unknown-8bit?Q?Jo=E3o_Carlos_Mendes_Lu=EDs?= <jonny@jonny.eng.br> Cc: "freebsd-amd64@freebsd.org" <freebsd-amd64@freebsd.org> Subject: Re: Actual benefits of amd64 over i386 Message-ID: <20050519054630.GC68698@dragon.NUXI.org> In-Reply-To: <4284FD37.2070009@jonny.eng.br> References: <BEA97082.3CD55%michael.hopkins@hopkins-research.com> <42842F46.9040608@samsco.org> <4284FD37.2070009@jonny.eng.br>
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On Fri, May 13, 2005 at 04:17:11PM -0300, Joo Carlos Mendes Lus wrote: > What about a 64 bit kernel, and mixed mode (32bit and 64bit) > userland? Solaris does this, and it sounds efficient, from the comments > I've seen in this list. When Sparc went from 32-bits to 64-bits the calling ABI was not changed. Nor were the number of registers increased. So it is w/o a doubt that a 32-bit Sparc binary runs faster than a 64-bit one (abit 64-bit math and large memory). This is not true of AMD64 - the number of registers was doubled and the calling ABI changed and optimized. > The bad part: Most (probably all) libraries would duplicated, and > the kernel and compiler should be modified to understand this "feature". We already duplicate all the shared libraries. > If amd64 32bit executables were compatible with (maybe the same) > i386 executables, even better. Note that I am not talking about i386 > emulation. I am talking about native 32 bit executables in amd64 arch. What is the difference of "i386 emulation" and "native 32 bit executables in amd64 arch"?? -- -- David (obrien@FreeBSD.org)
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